Hi,
In regarding of the issue, please provide us more information to assist you better.
- Which Office version do you use?
- Did the Excel files enable the "Shared workbook" function?
- Did you get the error massage like this "Document not saved"?
Then, I recommend we disable the "Offline File" to test, it'll help us to narrow down this issue.
If this issue still occurs after disabling Offline file, it might be caused by the temporary files that get created arent synchronizing correctly to the server share. Whats worse, the original files on the share are deleted and replaced with damaged TMP
files. Please try to delete all the temp file.
If this issue does not occur after disabling Offline file or get some "Access denied" error, we may try to check the connection between Office and Server 2012 R2. I recommend you post the question to Windows Server forum and get more help:
https://social.technet.microsoft.com/Forums/lync/en-US/home?forum=winserver8gen&filter=alltypes&sort=lastpostdesc
Thanks
George Zhao
Forum Support
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