Hello,
I have a user on Windows 7 Pro SP1 who suddenly cannot access MS Office 2010 documents on a shared drive on a 2008 R2 std. server. Yesterday it was fine as it has been forever and today he gets an "access denied" error when he tries to open an Excel or Word document stored on a shared drive. To the best of my knowledge nothing has changed. This user is not a "fiddler" and normally has no problems.

He has full permissions on that shared folder, first inherited through the "everyone" object on this "shared" folder and then, after the problem surfaced, through specific permissions I gave him on the sub-folder that holds the files in question . From the same location he can open other file types such as .PDF's, and he can copy and paste the exact same office documents from the shared drive to his PC where he can open them without incident.

I have gone to different folders inside this shared folder and looked at his effective permissions: He has full permissions at every point. It appears to be related to how Office 2010 is handling opening remote files. I have tried going though his normal mapped drive and through UNC paths with the same results.

I found this error id 300 in the application event log on the user's PC repeated many times. Here is the XML version with formating removed for display purposes:

xmlns="http://schemas.microsoft.com/win/2004/08/events/event <System>
Provider Name="Microsoft Office 14 Alerts"
EventID Qualifiers="0" 300
Level 4
Task 0
Keywords>0x80000000000000</Keywords>
TimeCreated SystemTime="2014-05-28T14:08:12.000000000Z"
EventRecordID>2901
OAlerts
Computer>HP-PC.MyDomain.local
Security
EventData
Microsoft Excel
Access denied. Contact your administrator.
701744
14.0.4763.1000