Hello Maria Luiza Pereira

I did think that this may at least contributing to the issue- 

Unknown said:

One of the files looks empty (for a mysterious reason).

and would explain possibly the error 'non-existent root element' as Studio cannot read the file or the necessary data to open the file.

Are you able to remove the offending file from the project?

If you have been using a TM, then you should not need to start the projects from scratch as all your translations from this projects should be stored in the TM.

Then you can simply pre-translate from the TM- which will get you back to where you left off.

Maybe I can call you or set up a remote webex and walk you through the steps needed.

Hello Steven,

I am still not able to recover my translation work. Just to let you know I am using TM. But I actually lost my recent translate work because I had to import the file from project package again to my computer. So I think I cannot do anything more about this file. However, I do have another one that something happen (error message).

Looking forward to hear from you.

Thanks