As of about a week ago, give or take, I have two users, both running the latest version of Office 365 (1803 Build 9126.2116) - One running Windows 10 Pro 64 bit, the other on Windows 7 Pro 64 bit, that are reporting that they are receiving errors when attempting to save various Excel files to a network share. The files are hosted on a local, Windows Server 2012 R2 server. When the users make a modification to an Excel file, the user will receive an error, "File not saved". As mentioned before, this only started happening about a week ago, as far as I know, nothing on either the client or the host PC has changed outside of maybe a Windows update.
Pulling up the Event viewer on one of the clients, I'm not really seeing anything specific to the actual problem I am experiencing. I have the following application error logged related to Office: Event ID: 300 but my research seems to indicate this has something more to do with opening a file.
This problem also occurred on build 9029.2253 as well. I'll try to get more information as I receive it. But it's somewhat of a mystery at this point as to why Excel is doing this all of a sudden. The users are able to access and modify other files, work in QuickBooks 18 Enterprise without issue. I have checked permissions for folders and files in the share and they all appear to be appropriate. I was hoping someone might be able to chime in here with some insight.
I have instructed the users to try an Open & Repair through Excel to see if that alleviates the problem.