Error in loading .mat file

Dear community:

I've encountered the below error massage when I was loading .mat file that has been successfully saved previously.
Perhaps the mat file became corrupted somehow. So I tried to load bakfile.mat, but the same error appeared.
I've been conducting several second level analyses so far, and it seems that the data files remain safely in D drive. 

================================
ERROR DESCRIPTION:
Failed to load file D:\LPP_fMRI\conn_project09_20210609.mat.
Error in conn (line 4686)
conn('load',filename,true);
Error in conn_menumanager (line 121)
feval(CONN_MM.MENU{n0}.callback{n1}{1},CONN_MM.MENU{n0}.callback{n1}{2:end});
CONN20.b
SPM12 + DAiSS DEM FieldMap MEEGtools
Matlab v.2019a
project: CONN20.b
storage: 193.0Gb available
===============================
Are there any ways to recover the .mat file? Or do I have to do the analyses again from the beginning?

Thank you in advance.
Best regards,

Silvia