I have updated to 3.0.2 to 3.0.3 and now is impossible open CopyQ for this error.

After uninstall and reinstall the previous same problem.
CopyQ 3.0.3 + XP.
same problem here, try 3.02 or 3.0.1 that will run ok on Win XP.
I took the *.zip, not the installer!
You are right, my situation is:
Portable:
3.0.3 = get error;
3.0.2 = works;
3.0.1 = works:
Installer:
3.0.3 = get error;
3.0.2 = works:
3.0.1 = not tested.
The difference is that latest version of CopyQ uses Qt 5.9.
Looks like this issue (closed because Qt is no longer supports Window XP).
You can try using the app built with different compiler from here -- but it may require to install some libraries which cannot be bundled with the app.
Thank you very much for the info, for now I remain with version 3.0.2 waiting to change O.S. very soon.
Since it's not difficult to build the app again with the older version of Qt, here is CopyQ 3.0.3 built with Qt 5.7 for Windows XP. This should definitely work.
Thanks, works fine!
@hluk
I am not using _Windows XP_ (_Windows 8_ here) but just asking- have you considered releasing an official _Windows XP_ version of CopyQ built with Qt 5.7? Such official _Windows XP_ version would spare time both for the users (opening issues) and for you (responding to issues).
@smaragdus I was thinking about that too. AFAIK there are currently no app issues connected to Qt 5.7 on Windows. Currently, the only reason to move to new Qt are that it could solve some issues in future.
Closing. If you still have this issue please reopen and provide details.
Most helpful comment
Since it's not difficult to build the app again with the older version of Qt, here is CopyQ 3.0.3 built with Qt 5.7 for Windows XP. This should definitely work.