FYI, I have this problem in slightly different form starting today also. “No such directory” followed by corrupted symbol path and *.qsch path. (The message has backslashes removed as does the OP.)
I’m having this issue too. The "" characters in the filename are missing and it can’t find the library. If I open the Symbol Properties, click on the Library File to open a browser and then point to the library, it fills in the correct path but still doesn’t run. I had to go in and put double slash “\” characters as dividers instead of single "" characters to get it to work. Must be a bug as I can’t imagine having to do this for every diode component.
I am also having this issue after updating today (Windows 11). I’m using one of the default selection options for a zener diode and getting the error “Fatal error: Could not open file “C:UsersjasonbQSPICEZener.txt””