Cannot write file "D:\FreeFileSync.ffs_lock" with new FreeFile Version

[Cmanincol]

I have used FreeFileSync on trial for a few months with no problem, but today I updated the version and am now frequently receiving the following error message:
>>>>>>>>>>>>>>>>>>>>>>>>>>>
Creating File "D:\ FreeFileSync.ffs_lock"
Warning
Cannot set directory locks for the following folders:
Cannot write file"D:\ FreeFileSync.ffs_lock"
ERROR_PATH_NOT_FOUND. The system cannot find the path specified [Create File]
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
I am using Windows 11 and backing up to an external hard drive.
Although I have disregarded the warnings and continued with my backup, and the backup seems to be complete, I now have no confidence in the real integrity of this

Free File Sync Error 241111.png (333.57 KiB) Viewed 616 times

backup.
Please explain why I get this message, what are the implications of the message and how can I remove the problem.
Thank you.