The first error is the important one "ERROR: Unable to migrate … "
SYSTEM ERROR 0. 
– means you didn’t get the settings correct. (Apply to this folder, sub-folders, and files – when granting permissions)
We need to erase the empty DSM 7 installation
– Uninstall the DSM 7 app and click the ERASE radio button (red one)
Next,
We can fix this.
Go here, Scenario 2.
You want to start at “Step 4: Change the shared folder permissions using”
You want steps 4 & 5.
Do everything there, exactly as shown. Don’t skip anything in the instructions (IMPORTANT)
When it’s complete, You will see “PlexMediaServer” has Full Control of everything in the Plex shared folder. (This is what we need)
Now install the DSM 7 plex app again.
-
It will sit at “Installing” for a while – this is expected
– It’s performing all the DSM 6 → DSM 7 migration steps
– Package Center doesn’t allow me to give you interim progress so I use “Migration.log”
– Open a second tab to DSM desktop
– FIleStation → Plex → Migration.log -
As you watch Migration.log (takes 2 minutes to show up / start updating)
you’ll see each step being started / completed. -
When you see Completed: Clean /volume1/Plex, then it’s done.
