My users can't sync

I have a a PlexPass account and have set up a few users, all with PINs and all are set to Allow Sync.

When they try to sync something on their tablet, they get an error saying “User has synced content on this device. That content must be deleted before you can sync with your current account”.

If they log in with my user account/PIN on the same tablet, it works fine.

Sync is only possible for one Plex user account per device.
If your user already has content synced to the device, a different plex user cannot sync to the same device.
Pretty much what the error message says.
Log into your plex user on the device, then delete all synced content. Then switch Plex user.

Note, other users can see and playback synced content, but they cannot add or remove them.

@OttoKerner said:
Sync is only possible for one Plex user account per device.
If your user already has content synced to the device, a different plex user cannot sync to the same device.
Pretty much what the error message says.
Log into your plex user on the device, then delete all synced content. Then switch Plex user.

Ok, but this is a user who signed in as him on a device I’ve never even seen let alone touched or logged into, and he doesn’t know my Plex PIN.

@markmcrobie said:
Ok, but this is a user who signed in as him on a device I’ve never even seen let alone touched or logged into, and he doesn’t know my Plex PIN.

Then I don’t understand

If they log in with my user account/PIN on the same tablet, it works fine.

@markmcrobie said:
Ok, but this is a user who signed in as him on a device I’ve never even seen let alone touched or logged into, and he doesn’t know my Plex PIN.
It doesn’t have to be your account that is the other account. i.e You’ve shared with both a friend and their significant other. One of them logged into the device to sync some stuff. The other logs in with their user but will not be able to sync.