Outlook Cached Exchange Mode is grayed out

Category              : Outlook 2007
Operating System : Vista

Symptoms            : Outlook status showing Online with Microsoft Exchange
Error Message      :  nil

(for advance users who are searching fix for Outlook Cached Exchange Mode grayed out issue, please scroll/skip down  to FIX - Outlook Cached Exchange Mode is grayed out)

Well some of you guys might have encountered this issue, whereby when you are connected to office network, your outlook works find, but when you open outlook at home, outlook gives variable error messages and inbox become empty.

It happens because (on layman words) : the outlook have failed to find/create OST file , OST file is a copy of all the messages (inbox) into you hardisk, as for the fact the outlook inbox is directly connected to the exchange server and not located in local machine.

Therefore, your outlook (inbox) is directly connected to exchange server without any copy in hardisk, this is why outlook will only work at office network (direct exchange connection) and not at your home (offline).

So how to check? outlook status will be indicated as "Online with Microsoft Exchange"

FIX

To fix this problem, click on Tools > Account Settings..

Double-Click on your email address

Tick on Use Cached Exchange Mode check box

Click Next > Finish. Relaunch outlook and outlook will start updating / creating ost file. The outlook status now will become Connected to Microsoft Exchange.

Well sometimes the Use Cached Exchange Mode check box will be grayed-out. This might cause by several factors like group policy. Below will be the registry key which need be modified to enable the option.

FIX - Outlook Cached Exchange Mode is grayed out

1. Start a admin cmd (command prompt) window

2. Type regedit in the admin cmd window to launch Registry Editor

3. Go to HKEY_USER\User SID\Software\Microsoft\Office\12.0\Outlook\OST

4. Right click on the NoOST entry on the right and click Modify

5. Give it a value of 0

6. Restart Outlook 2007 and the Use Cached Exchange Mode option should no longer be grayed out anymore.

                                                           !!cheers!!