Hi,
The client freezing during the manual sync option could be due to the large number of spaces and files in your OwnCloud instance, causing high RAM usage. Since you only need the personal space for sync, try narrowing down the sync scope to just the personal space. This might reduce resource usage and improve client performance. If the issue persists, consider checking for updates or reaching out to OwnCloud support for further assistance. Let me know if you need any more help!