Studio 2019, files disappear from C:\Users\MyName\AppData\Local and I cannot go on working... What can I do to repair / prevent this?

Hello,

Files disappear from C:\Users\MyName\AppData\Local and I cannot go on working properly... 

The files seem to be a copy of the source xml-texts (which I don't have), but under a very different name, i.e. dz2z5v25.xml.xml

When trying to open the bilingual file, I get an error message. If I can nonetheless open the file and work, QA tools won't work.

How can I tell my PC not to delete those files? Is it possible to find them again?

Many thanks!

Caroline