If a Windows Stage 1 Sync or Host Sync fails with
SYNC_ERROR_TRANSFER
read errors mapping "/cygdrive/<drive letter>/<file name>: No such file or directory"
it indicates that filename shown in the error message was not in the Windows snapshot of the drive at the time the RMM was trying to copy it.
If there was some unusual activity on the source server at the time of the sync, or if there happened to be a higher rate of change than usual in the files on the drive at the time of the sync, then simply retrying the sync may work.
If this happens more than once, the windows snapshot size should be increased. This should be discussed with the Windows system administrator of the source server.
In order to do this, ssh to the Windows source server and then issue the command
vssadmin list shadowstorage
This will show the current windows snapshot settings.
Rackware recommends having the snapshot size be 15% of the size of the drive. But servers that have a very high rate of change of the data on a drive, that might not be enough. The CLI command below will change the max shadow copy size for the T drive to be 20% of the space on the T drive
vssadmin Resize ShadowStorage /for=t: /on=t: /MaxSize=20%
Note that the size of the shadow copy for the T drive can only grow to be 20% of the size of the T drive if there is enough free space to hold that snapshot. So if the T drive is 1000 GB, and you want the max snapshot size of the T drive to be 20% of the drive size, then there needs to be 200 GB free space on the T drive.