I've noticed Logos continually syncing (spinning sync icon) on two occasions without generating the red error symbol.
On closing the app, the Sync window appeared and did not disappear until I clicked "Exit Now". When Logos was re-started, the Logos 9 banner appeared but Logos did not open. After forcing it to close, I noticed a large, active background task 'Logos Bible software'. Logos started normally after the background task was forced to close, and Sync completed after a short time.
On this second occasion, I closed the active background 'Logos Bible software' before re-starting and normal service was resumed.
The log shows a SyncManager request that started at 0859 and did not terminate at 1545, when Logos was exiting.
4380.Syncing.zip
Memory usage was about 47% in both cases and the foreground tasks were about 1040-1080 MB whilst the background tasks were slightly smaller.