Microsoft Office cannot complete the operation because the network is unavailable. Check your network connection and try again.
This issue occurs when a user attempts to check in/out a document while inside of a Microsoft Office client (Word, Excel, etc).
Check the version of Anti-Virus. In the case I ran into, Kapersky Anti-Virus was causing a “network awareness” issue where it caused office to think the laptop or desktop is offline. You can tell by looking at the network indicator, it will have an exclaimation point. After updating the version of anti-virus, this was no longer an issue.