Files saved using the autosave function are stored in the MxTemp folder. The path to this folder is as follows: AppData > Local > Temp > MxTemp.
This folder may also contain backup files in the format filename.tmp. These .tmp files originate from an older version of Matrix Software and can be opened using the appropriate version of the program.
It is possible that the user did not enable the autosave function. In such cases, it is still recommended to check whether these types of files are present.