We ran the gamut of trying to figure out the following error:
Cannot open your default e-mail folders. You must connect to Microsoft Exchange with the current profile before you can synchronize your folders with your Outlook data file (.ost).
Cannot open your default e-mail folders. The file C:\Users\UserName\AppData\Microsoft\Outlook\UserEmail@Domain.ca – First.ost is not an Outlook data file (.ost).
We tried everything from recreating her Outlook Profile, removing the OST file just in case it was corrupted, a number of combinations including the aforementioned steps along with others, and finally flattening her local profile and starting fresh.
It was not until we signed into a desktop OS VM with the user’s credentials after they mentioned that Outlook threw the same error for them when signing into a spare laptop that it became apparent that we were dealing with a server problem.
There was no clue that the problem was with SBS 2003 and Exchange 2003 because no other users were complaining about a Disconnected Outlook.
After combing through the logs on the SBS 2003 server we turned up the following:
Event ID: 9646 MSExchangeIS
Mapi session “/o=DOMAIN/ou=first administrative group/cn=Recipients/cn=Username” exceeded the maximum of 32 objects of type “session”.
Searching for this error brought us to the following KB article:
- Microsoft Knowledgebase KB842022: Event ID 9646 is logged in the application event log of your Exchange Server 2003 computer when a client opens many MAPI sessions
We needed to add the following registry key and restart the Information Store on the problematic server:
- Click Start, click Run, type regedit in the Open box, and then click OK.
- Locate and then click the following registry subkey:
- If the Maximum Allowed Sessions Per User entry does not exist, do the following:
- On the Edit menu, point to New, and then click DWORD Value.
- Type Maximum Allowed Sessions Per User as the entry name, and then press ENTER.
- Right-click the Maximum Allowed Sessions Per User entry, and then click Modify.
- Click Decimal, type the value that you want to set in the Value data box, and then click OK.
- We used the value of 128.
- Exit Registry Editor.
- Click Start, click Run, type services.msc in the Open box, and then click OK.
- Click the MSExchange Information Store service, and then click Restart Service.
We confirmed that the Information Store restarted properly and our stores were mounted. We then started Outlook on the user’s system and were finally greeted with their mailbox!
Note that the user was using OWA when the problem started so it did not become apparent that the problem was on the server until _well_ into this troubleshooting process.
Microsoft Small Business Specialists
Co-Author: SBS 2008 Blueprint Book