SBS 2011 Server. Windows 10 Professional workstations. Spreadsheets are kept om the server. The issue is that everyone (20 users) on occasion has Excel jet-lag to the point they have to turn their computers off.
No sign that the server or switches are over utilized. There is nothing consistent about the problem other than maybe the more spreadsheets they have open at the same time the greater the odds of it happening.
I have replaced computers and switches. The only thing I can think is Excel is doing something in the background like backing up or caching or some kind of disk I/O. Is there any way to tell Excel to use the local C: driver for and type of intermittent file backups, caching, temp files, whatever?