VS 2021 crash "could not find the Qt platform plugin"

[JBR48]

First post on this forum. I recently bought the VS2021 upgrade. I had VS2019 installed before and it worked fine.
After installation the program seems to start up normally, but after completely loading, it will present a requester with a cryptic message.

"This application failed to start because it could not find or load the Qt platform plugin "windows" in "".
Available platform plugins are windows.
Reinstalling the application may fix this problem."

Closing the requester will immediately terminate the program. Note that before closing the requester the program seems to work normal, I can insert video clips and generate an output video.

I contacted support and it gave me a series of instructions to determine the problem, involving WinAudit and MSINFO23 reports. Then came a sequence of actions involving uninstalling VS2019, uninstalling and re-installing VS2021 several times without any change in results. I finally stopped this, because I was afraid I might wear out my computer's reset switch .

I got the feeling that tech support was mindlessly following their scripts and did not address the actual problem. One question that I would have is that VS2021 seems to use the Qt framework and the problem is clearly with the setup of that framework. Perhaps there is a conflict between some software that I already use and the Qt framework.

1. Is the Qt framework used in the main application or is it used only in a helper function that I could perhaps disable or uninstall?

• Perhaps I could install Qt libraries from another source and install and test those separately? I have used Qt under Linux, so I am somewhat familiar.

Given some time I could probably come up with more debugging strategies, but before I spent too much time, I was wondering if any members have experienced similar problems or perhaps have other suggestions. I look forward to your thoughts.

[Ken Berry]

Welcome to the forum.

Your problem is totally new to me, unfortunately. I've been on this forum for a long time, and this is the first time I have heard of this (or as much as my ageing brain can recall!) When I saw "Qt" I immediately thought it was a Quicktime problem. But of course on googling it, I see it is deeper than that. Hopefully someone who knows more about it will come along soon to help you.

I assume, however, that you have already googled it yourself. There seem to be quite a few "solutions" out there. One caught my eye in that it contains quite a few relatively clear steps. But it is at least worth reading if you have not already: https://forum.qt.io/topic/90293/could-n ... dows-in/14

[JBR48]

Hello Ken,

Thank you for the quick reply. I totally missed your google result, I probably included VideoStudio in all my searches. The discussion in that thread is talking about the exact same error message that I get, so it is very relevant. The solution given is to remove a directory from the global PATH that contains the wrong version of qwindows.dll.
In my case it turns out that I have 37 (!) instances of qwindows.dll somewhere on my computer, but none of them are on the global PATH. Also VideoStudio does not have qwindows.dll anywhere in its installation.

One possibility is that some VideoStudio component does require Qt, but it is missing from the installation. That would explain the message that the Qt platform plugin cannot be found. I will follow up this line of investigation.

Regards,
Jan

[lata]

Jan…..
I have searched my C:Drive for qwindows.dll finding 16 entries
Associated with the Corel Installation are............

C:\Program Files\Corel\Corel AfterShot 3\build\Plugins\platforms
C:\Program Files (x86)\NewBlueFX\Common\platforms
C:\Program Files\NewBlueFX\Common\platforms
C:\Program Files\NewBlueFX\Titler\platforms

New BlueFX is installed by Video Studio Ultimate as part of the Bonus Features folder, shows as NewBlue Titler Pro 5 in the FX library
Re-Installing Video Studio may not remove the NewBlueFX folder nor remove “qwindows.dll”

You would be best to view Program and Features for NewBlue Titler Pro for Corel or Titler FX entries, uninstall then delete or rename the NewBlueFX
Now try running Video Studio 2021

Install the package from Bonus Features folder by running the "setup_Bonus.exe", or re-install the entire VS 2021 program
Your download program files …… \64bit\BonusFeature

That should replace the “qwindows.dll” file

If the problem persists I would download the installation files again to a new empty folder -- just in case the original downloaded installation files are corrupt
You would have to uninstall 2021 to download the files again.

[JBR48]

The google link that Ken gave me was the crucial link to solving my problem. But in contrast to the problem in the google link my problem was not that the wrong qwindows.dll was on the $PATH$, because it wasn't. But there were directories for NewBlueFX in both C:\Program Files (x86) and C:\Program Files. NewBlueFX is of course part of (older) VideoStudio installations, which were not uninstalled automatically, but still managed to affect the newest installation of VS2021. Removing those directories immediately solved the program crash.

I was now afraid that I had removed the NewBlueFX functionality from my computer, but it turns out that that functionality is now wholly contained in the directory C:\Program Files\Corel\Corel VideoStudio 2021\vft_plug. There are no longer separate NewBlueFX directories.

The strange part is why VS2021 keeps looking for qwindows.dll in the old directories, while it now has moved this functionality to a new place. I cannot imagine that my computer is the only one that has (remnants of) older VideoStudio installations floating around. I think I had 10 separate VideoStudio versions installed at some point (maybe not all on my current computer). Clearly some stray code in VS2021 remaining from previous versions? Tech support should take a look at that.

Update I have now had time to read the post by lata. He gives the correct analysis of this problem and I thank him for contributing. I have a few remarks:

He finds the qwindows.dll in the same places as I did. His advice to uninstall NewBlue is excellent, but I was not able to locate a way to uninstall, since it was no longer in the Apps & Features list. Just deleting the directories seemed to do the trick, however. Re-installing the bonus features was also not necessary, since they were correctly installed the first time. Also the VideoStudio2021_Installer.exe seems to pull everything from the internet, there do not appear to be folders with bonus software like ..\64bit\BonusFeature anymore.

[lata]

Update I have now had time to read the post by lata. He gives the correct analysis of this problem and I thank him for contributing. I have a few remarks:

He finds the qwindows.dll in the same places as I did. His advice to uninstall NewBlue is excellent, but I was not able to locate a way to uninstall, since it was no longer in the Apps & Features list. Just deleting the directories seemed to do the trick, however. Re-installing the bonus features was also not necessary, since they were correctly installed the first time. Also the VideoStudio2021_Installer.exe seems to pull everything from the internet, there do not appear to be folders with bonus software like ..\64bit\BonusFeature anymore.

When we purchase Video Studio or install the trial we are provided with a small file called “VideoStudio_Install.exe”
If you are lucky then it will be called “VideoStudio2021_Installer.exe” that identifies the version, other wise 2021 version file is 7,091Kb

Think of the file “VideoStudio2021_Installer.exe” as a download / Installer manager.
Running this will allow us to enter our serial number, register then proceed to download and install the program
The downloaded files are saved by default to the desktop in a folder aptly called “VideoStudio2021”
We do have the option to choose another save location should we wish to do so.
The total size being 5.7Gb ish

Here you should find the installation files containing folders………..
64bit, Common, StandardContent2 and also a copy of VideoStudio_Install.exe
Viewing the contents of 64bit you should find the Bonus Features, that is assuming you have purchased the Ultimate version and not the Basic Pro version

Re-installing 2021
This will use the same process as above and will also check the existing files for any changes / updates on the Corel server to download any new files to the same save location
If you wish to download the complete package again then choose a new empty save location folder, the web installer will then download all files again, useful if we think the first download files were corrupt.


Program and Features entry for NewBlue Titler Pro for Corel may not be showing even though the plugin is installed, this may be a problem with multiple installations of 2019 and 2021 (Version Collisions)
Should the fixed by running Bonus Features "setup_Bonus.exe" for 2021.

OK
NewBlueFX
If you have either renamed or deleted the folder NewBlueFX from C:\Program Files\NewBlueFX then the filter in FX library although will show will not work giving an error when trying to use.
However if Video Studio and NewBlue is working with no qwindows.dll. errors then I guess you have fixed the original issue.

[cbleek]

I had the same problem!

After de-install NewBlueFX Titler 5, everything works withot the error massage.
When re-installing NewBlueFX Titler 5 again, the error message returns!
So, that plugin causes the issue!

Fun Fact: I had Corel Video Studio 2018 before and also had a lot of trouble with this NewBlue Titler5 (VS crashes when using the plugin).
The support bothered me with copy-paste of there standard FAQ knowledge (plz re-install VS,...) and they were not willing to search and find a solution...

What a pitty that there are still some troubles with this 3rd party plugin...
So I am damned to use the software without this title generator, which is disappointing.
The internal vs title creator is really basic...

[kwarner]

So how does on uninstall NewBlueFX? There is no separate program in the Windows Apps & Features listed. I found a NewBlueFX folder in Program Files with an uninstaller full of .exe programs. But which one to run?

I just bought a copy of VS 2021 Ultimate Upgrade after not using VS for about 6 years. Installed on a new computer so no previous installation to mismatch with. On starting VS, I get the error dialog box "This application failed to start because no Qt platform plugin...", and then VS exits. Tried reinstalling. Still fails on start.

I go down the path described in Ken's link next for finding the bad DLL path. But how does this happen with a clean installation? Corel's installation testing should catch this!

[lata]

Hi kwarner
Sorry you are having problems here
Difficult to replicate as I have never had this problem.

Uninstall Video Studio, use the Cleanup tool
https://forum.corel.com/viewtopic.php?f=1&t=59847

Installing the program again but this time choose Custom / Modify, then deselect Bonus Features, that should install the program without NewBlueTitler.
If video studio now runs you can run the Installer again to install the Bonus Features

Otherwise you can manually run the Bonus Features package
You will find the Bonus Features folder withing the 64Bit folder of your Downloaded folders.
Locate this file “setup_Bonus.exe” double click to run.

Video Studio will now be fully installed

Note… as above I have ran a few install tests and NBTP5 does not show in Program and Features, I do know it did show in the past, so maybe Corel have updated the way that plugin installs
I’ll have a look to see how to remove NBTP5

Post Updated
From your pc start menu is a link for New Blue with an option to Uninstall NBTP, I ran that, unfortunatley the plugin still works using 2021, confused..........

[kwarner]

Thanks lata. I've got it working but I'm not sure why the error message disappeared or if everything is installed correctly. I mostly followed your instructions:

1. Uninstalled using the Windows Apps & features
2. Downloaded the Video Studio 2021 Cleanup tool and ran it. Looked like it just cleaned out some registry entries
3. Ran VideoStudio_Install.exe to reinstall Video Studio
4. Selected Custom/Modify
5. Unchecked Bonus Features and proceeded with the install
6. Started up Visual Studio and program started up with no errors confirming that the problem was in the Bonus Features
7. Went to my Visual Studio install files and into the directory \VideoStudio2021\64bit\BonusFeature. The install files might be on your desktop or as in my case, a local copy that I made on a second disk. I ran the file setup_Bonus.exe.
8. Started up Visual Studio again, expecting to see the "no Qt platform plugin..." error again. But NO ERROR MESSAGE! Hurrah!

So did all the Bonus Features get linked into Visual Studio correctly? I don't know what functionality NewBlue Titler Pro 5 provides so I couldn't verify it was installed. I did see a 3D Title Editor button. In the same directory as setup_Bonus.exe is another file named BonusInstallerList.ini. It looks like a manifest for all the bonus plugins. I was able to find signs that those plugins were installed under FX|proDAD. So it looks like the Bonus Features were installed properly.

Some miscellaneous info:

• Ken's link pointing to a bad environment variable was not the problem in my case. There was no QT_PLUGIN_PATH in my environment. Nothing related to Visual Studio at all. As I mentioned, the machine I'm using is new and relatively clean.
• The directory C:\Program Files\NewBlueFX\uninstallers had a lot fewer files than when the Video Studio installer did a default installation. My manual Bonus install has only 3 files. The default had something like 12 uninstall files.
• I opened a support ticket with Corel but haven't heard anything back yet.

[lata]

Hi
I am away from my pc for a few days so cannot compare installations
I would assume manually running the Bonus Features would install the same as an auto installation.
I do not really understand why you would think that the installation is not complete.
Can you be more specific and give details of the parts you believe are missing.

NewBlue Titler Pro 5, should be available from the FX library, bottom of the list.

[kwarner]

I'm a software engineer by trade so have seen software built in all kinds of ways. Just running a program named "setup_Bonus.exe" may not be the whole story on installing the bonus plugins. What I'm particularly concerned about is if some command line options may be needed. The differing number of files in the uninstallers directory leads me to believe there is something different about the manual Bonus installation (besides the Qt problem).

If you have better things to do, I'm satisfied with my Visual Studio running without startup errors now. I may try another uninstall-install to compare results more. The BonusInstallerList.ini has me intrigued because some entries match with the file directory structure and others don't.

Thanks for your help.

[lata]

Kwarner
Just to correct any confusion the program is called Video Studio not Visual Studio
I know little about the file directory structure nor how to compare the auto install to the manual approach.
Even re-installing using both methods is also difficult to compare especially where we have other versions of Video Studio installed.
NewBlue Titler Pro 5 is installed by all versions as are most of the Bonus Features content.
I believe NewBlue Titler Pro 5 installation process has been updated by Corel as it now appears to be portable (if that’s the correct description) in that it no longer appears in program and features.

I am away from home at the moment and do not have access to my pc to check the BF files although I have never noticed a difference when installing using either method, all content seems to be installed.

The manual approach being used to overwrite and fix problems avoiding a full re-install.

[kwarner]

Haha. My apologies. If you're not familiar with it, Visual Studio is Microsoft's tool for writing PC software. I used it for many years. I start typing Vi... and Visual comes out of my fingers instead of Video . I'll try to be more careful.

As an experiment, I configured one of the PCs I use for software testing in as clean a state as possible. It has an older Intel i7-3770 CPU w/ 8GB of memory. Removed all drives and installed a brand new SSD and installed Win10 21H1. Downloaded and installed all MS updates. This is as clean as a PC can get. I then went to videostudiopro.com and downloaded the installer and reinstalled Video Studio with all features.

The installer finished and gave me two buttons: Launch VideoStudio and Finish. I pressed Launch VideoStudio. The splash screen came up and then the program promptly crashed. *sigh*

Ok. I'll give it another chance. Rebooted in case there was some cleanup needed. Clicked on the Corel VideoStudio 2021 desktop icon. Splash screen came up...then the Welcome screen..........and NO "failed to start because no Qt platform plugin" error message. It worked!

Now I can press all the buttons and see what is behind them. I can press the FX filters button and see that NewBlue Titler Pro 5 is there. So this is what Video Studio is supposed to look like.

What can be learned from the second working Video Studio installation:

• Not installing Bonus Features on initial installation and then running setup_Bonus.exe later does NOT result in installing all the Bonus Features.
  NewBlue Titler Pro 5 was not installed when I did that.
• The full installer created 9 files in the NewBlueFX\uninstallers directory. Running setup_Bonus.exe only created 3.
• The difference between a working installation and an installation with the Qt error message is the difference between my old Intel i7 PC and my new AMD Ryzen 5 5600. My relatively "clean" new PC may have some conflicting software. Could be my antivirus program.

Next experiment: Move SSD to my Ryzen PC, do a clean Windows install, and test Video Studio. Then add programs and see which one breaks Video Studio.
Will have to wait awhile as my Ryzen is tied up with real work right now.

[lata]

Kwarner
Thanks for the update on this issue and for the efforts you are putting in.

First the initial start of the program creates several folders one being here
C:\Users\trevo\AppData\Roaming\Ulead Systems\Corel VideoStudio Pro (x64)\24.0
That is used to reset the program. The creation of these extra folders does slow down the start process, and yes I have experienced the first fail but always starts on the second go, a little quicker to launch than the first attempt.

There have been some issues where more than one program is installed, described as Version Collision by Corel, as some plugins are shared across different versions, uninstalling say 2021 could affect the content of 2020, I believe NBTP5 and MyDVD and some Prodad stuff may be affected. Same for uninstalls affecting other programs. Yes I realise you are only running 2021.

The NBTP5 used to have an entry under Program and Features, I am sure of that, but that longer shows, so Corel have updated the way the installer works over the last few versions, from 2019 that is..

As for manually running the Bonus Feature, I guess that is our attempt at fixing things and not an official Corel option, It does however overcome some issues where a full re-install would be required.
I will pay more attention to the installation of NBTP5, next time I reinstall but am aware of some similar MyDVD installs, where running the VideoStudio_Install.exe again shows the Contents as not being installed. That’s another story.

None of the above actually stops the program from running so the user is not aware of anything amiss.