Images opening in X7 instead of X9

[Nitro]

I have both PSP X7 and X9 (32 and 64 for both) loaded on my Windows 10 pc and whenever I try and open a pspimage or png image it opens in X7 then I get an error message '"unable to open the file. Please verify that the file is valid". This is annoying and extremely frustrating as well as time consuming. When working on an image I save as a pspimage as I go along and if I have to go back to a saved step I have to be soooooooooo careful how I click on it as the only way I can get it back in X9 is to drag and drop. Prior to upgrading to a new pc with X9 and windows 10 I had/have Windows XP loaded with PSP 10, X2 and X7 and never a problem. The only solution I can think of Is to delete X7 and yes I do use it, although less frequently lately.
I hope someone can help me with this and it is probably a simple solution (hoping so anyway!)
thanks

[hartpaul]

I presume that you are sometimes using PSP X7 and saving images in pspimage format and also sometimes working in X9 and again saving images in pspimage format.
You will find that any image saved as pspimage from X9 will cause errors if opened in X7.

Are you double clicking the image and finding it opens in x7 and if that image was from X9 then you are getting an error or just dragging a pspimage from a mixed folder of X7 and X9 images and finsing that any X9 ones are causing an error in X7?
If you only save X7 images in an X7 folder and X9 ones in an X9 folder then you should not have a problem when you drag and drop.
Also you can use an option in X9 to save it as a pspimage backward compatible to X7 . Not sure if setting that remains constant from session to session or if you have to do that adjustment everytime.

As to removing X7 some would advise to keep it just in case something goes wrong with X9 and you then need to use X7.

If you are opening psp and an image and wasnt it to open in X9, you can also user right click and in the context menu Open With X9

[Nitro]

Thank you for your reply .. and I do keep my X9 work in folders separate from X7. I am not able to either single or double click any work in the X9 folders saved as X9 png or pspimage without it opening X7. If I save backwards to be compatible with X7 that really won't save my problem when I am working in X9 it will just mean I won't get the error message and it will still open and therefore will have to close 7 down to get back to X9.
I think I have solved my problem ... I went into my pc system default application settings and X7 was the default for all things PSP - so I changed the problem extensions to X9 being the default. I have never looked in that area of my pc before ... interesting!
Thanks for your suggestions - and now I can leave X7 where it is!. The alternative -using right click and open with - would have been my option