I am using 6.81B2 with a download folder configured as
i:\Downloads\$(GROUP)\$(SUBJECT)
This mostly works but somtimes downloads stop with "ERROR Insufficient Disk space to continue" and path where the last directory name consists
strange characters, eg
1 pbW_J}ÛXW_¹dBêîTq7T2«\
This blocks all all the following queued downloads.
Also there are several gb of free disk space available on this drive.