The user can successfully save a MS Excel or Word file to a mapped drive. However when they next try to open a co-authored saved file this error occurs:
The document was saved successfully, but Excel cannot re-open it because of a sharing violation. Please close the document and try to open it again
Workaround:
1) Use UNC path to access file, instead of mapping network to drive-letter
2) Open Excel first and then access the file, rather than double clicking the file itself.
This is currently being tracked under EA-23784/DSEN-27167 and is scheduled to be fixed with the 4.0 MR2 release.