I found a couple of discussions about this issue from back in 2017:
The issue is marked as partially fixed/solved, but I am still encountering it in 2023. Specifically, when trying to sync, if rclone encounters a folder that is unreadable due to permissions, it doesn't just skip over that folder and continue with the other folders which are readable. Instead it aborts the sync for all of the sibling folders in that part of the directory tree.
So that if you have folder "parentfolder00" which has 99 subfolders called "subfolder01, subfolder02... subfolder99" etc... and try to include the parent in a sync, if it is the case that subfolder01 is unreadable for any reason, the sync will skip all 98 other folders which are alongside the unreadable subfolder 01, even if the other 98 are perfectly readable and have no errors. Other folders above this level of the directory tree will continue to be synced, but subfolder02 through subfolder99 will be ignored entirely, even though they and their contents are readable.
In fact, it isn't even only the sync command that is affected by this bug. You can even test it with a simple 'lsf' command like so:
rclone lsf /home/fred/parentfolder00
...to which the output is:
2023/07/04 23:47:35 ERROR : : lstat /home/fred/parentfolder00/subfolder01: permission denied 2023/07/04 23:47:35 ERROR : : error listing: failed to read directory entry: failed to read directory "/home/fred/parentfolder00/subfolder01": lstat /home/fred/parentfolder00/subfolder01: permission denied 2023/07/04 23:47:35 Failed to lsf with 3 errors: last error was: error in ListJSON: failed to read directory entry: failed to read directory "/home/fred/parentfolder00/subfolder01": lstat /home/fred/parentfolder00/subfolder01: permission denied
A simple lsf will fail to show even the existence of the other 98 subfolders, as soon as it encounters the one single unreadable subfolder.
Back in the 2017 threads there is mention of implementing a --skip-unreadable flag, but it doesn't ever appear to have been created. Really it should just be the default behavior of rclone to automatically skip unreadable folders and continue with the rest, but at the very least a flag would be useful to handle these instances.
Is there any known fix/workaround for this issue, other than specifically excluding the unreadable folders? That works fine if there are only one or two, but if there are dozens, it would be ideal to have rclone simply skip/ignore them every time.