Q: Office 365 for Business sync app for Mac (El Capitan)

Try posting your question here

http://answers.microsoft.com/en-us/mac/forum/macofficeo365-maconedrive?sort=repl ycount&dir=desc&tab=threads&status=all&mod=&modAge=&advFil=&postedAfter=&postedB efore=&threadType=all&tm=1450108494917

The OneDrive app is buggy and doesn't work well (as you observed). Users also report losing documents that are being edited directly on the cloud. Until MS gets it together, the workaround is to save locally to your hard disk, then manually upload to OneDrive.