*cdr file does not open after changing from *tmp file to *cdr file

hi, dear friends

I am new here - and sorry - but my English is not very well.

While working with an important job for 10 days with CorelDraw the cursor change to the "hand" and the file does not react. The only possibility was to finish the task with task manager.

I was in a good mood because I always save the file during the work with ctrl s.

Now I saw that there only was an old file from 2109-07-29

But a huge number of tmp files up to yesterday. The original cdr file is about 8.000 KB, the tmp file is 588 KB

I tried to open the last one while changing the ending tmp to cdr.

But the file does not open. CoresDraw says "Fehler lesen" in English: "reading error"

Please help me! It is very important for me!!!