Júlia Moll 

Have you tried to shorten the path to the file and/or the file name itself? Sometimes it was just the issue…

If Trados Studio works in a short folder and file, such as, C:\Test\test.docx, then the culprit may be the long path and/or file name.

How big is the path + file name in your project folder? You can copy & paste it to Word application and do the wordcount to know the exact length. If it’s around 250 chars long, you might get that error

Thank you for getting back to me.

The file name that Trados mentions is actually long, I'm aware of that, but I cannot find the file in my computer (i have looked for it follwoing the path that Trados provides in the error message) and it seems to be gone (deleted). How can I shorten it if it's not there?

Júlia Moll 

Is the path you mentioned in a temporary folder? If so, just forget about it.

Your XLIFF and your TM should still be on your PC.

What I mean is to shorten the path in your Project folder (the one opening when clicking this button on the Home ribbon) and/or the file name of the original file:

How big is the path + file name in your project folder?

Solved! Thank you!