Hello Vanessa Marques,

There are a number of reasons why Studio might be shutting down, so it's always a good idea to post the full error stack as this may indicate what is causing the problem.

Where are you storing your files/projects? If these are in the cloud, this could be a cause due to intermittent connectivity.

Here I would suggest creating a project locally and see if the issues is resolved.

Often unexplained issues can be resolved by Reset Windows Layout-

Or by repairing/resetting Studio

https://gateway.rws.com/csm?id=kb_article_view&sysparm_article=KB0039395

Ensuring Windows is completely up-to-date (along with drivers/graphic cards) can prevent a lot of issues as well as adding Studio/Multiterm to your AntiVirus providers exceptions list

https://community.sdl.com/product-groups/translationproductivity/w/customer-experience/3392/how-to-part-1-trouble-shoot-unexplained-errors-and-unwanted-behaviour-in-studio-multiterm

Parts 1&2)

Please let me know if you are able to resolve the problem (and if so what you did) or if you need further assistance.

Hello Vanessa Marques,

There are a number of reasons why Studio might be shutting down, so it's always a good idea to post the full error stack as this may indicate what is causing the problem.

Where are you storing your files/projects? If these are in the cloud, this could be a cause due to intermittent connectivity.

Here I would suggest creating a project locally and see if the issues is resolved.

Often unexplained issues can be resolved by Reset Windows Layout-

Or by repairing/resetting Studio

https://gateway.rws.com/csm?id=kb_article_view&sysparm_article=KB0039395

Ensuring Windows is completely up-to-date (along with drivers/graphic cards) can prevent a lot of issues as well as adding Studio/Multiterm to your AntiVirus providers exceptions list

https://community.sdl.com/product-groups/translationproductivity/w/customer-experience/3392/how-to-part-1-trouble-shoot-unexplained-errors-and-unwanted-behaviour-in-studio-multiterm

Parts 1&2)

Please let me know if you are able to resolve the problem (and if so what you did) or if you need further assistance.

Thank you for your reply, Steven Whale.

I'm not logged onto the cloud.

Someone told me "that happened to me a while ago, the .sdlxliff file went corrupt for some reason and I wasn't able to work on it anymore. I suspect that the synchronization on Google Drive could have caused that, because when I checked the project folder, the file had been renamed due to a conflict and Trados wouldn't open it anymore (therefore, the error message also said that the file didn't exist, exactly like yours). If you use Drive, Dropbox, OneDrive or similar apps, that could be a reason. You should then deactivate them and synchronize the files with the cloud only after you finished work for the day." 
This could be the case as the only time this happened I was logged onto Google Drive.