Hi all, I have been using O365 for 12 months.  Last week Outlook stopped working properly - never had a problem before then.  The only thing I did (that I know of) was I deleted a mailbox from the navigation pane on the left hand side (right click - remove).  Since then, nothing but grief.

I can start Outlook in Safe mode no problems.

I have tried everything on this post http://community.spiceworks.com/topic/467572-outlook-2013-does-not-open-but-opens-in-safe-mode

including

I have disabled every single Addin.    

I have checked that harware acceleration is turned off

I have tried outlook.exe /resetnavpane

I have deleted my profile and started again from scratch (3 times).

I have uninstalled and reinstalled O365.

Nothing is working.  When I start Outlook in normal mode, it just hangs on the splash screen.  Interestingly, I can right click on the Outlook icon on the task bar and select any of the options (new message, new calendar entry) etc and they all work.  The issue is that the main screen with the inbox and navigation pane wont load.

Does anyone have any ideas that might help me?

I found another post that suggested disable hardware acceleration from the UI rather than the registry.

File\Options\Advanced\Display\disable acceleration

 I tried this and now Outlook will open, but it is still not quite right.   There are now 2 windows I can see in the task bar. One of them I can use and the other one is just sitting there "blank".  If I select it, nothing happens.  I can close it, but it returns when I restart Outlook.  Also if I go into the UI and right click on "Calendar" I used to be able to open a second window - 1 for inbox and 1 for calendar.  The second window opens but I can't use it - it is the same as the one I describe above.

So it is "half working" now, but any advice on how to fix the residual issue would be appreciated.

• Edited by Matt Allington 8 hours 9 minutes ago

I found another post that suggested disable hardware acceleration from the UI rather than the registry.

File\Options\Advanced\Display\disable acceleration

 I tried this and now Outlook will open, but it is still not quite right.   There are now 2 windows I can see in the task bar. One of them I can use and the other one is just sitting there "blank".  If I select it, nothing happens.  I can close it, but it returns when I restart Outlook.  Also if I go into the UI and right click on "Calendar" I used to be able to open a second window - 1 for inbox and 1 for calendar.  The second window opens but I can't use it - it is the same as the one I describe above.

So it is "half working" now, but any advice on how to fix the residual issue would be appreciated.

• Edited by Matt Allington Sunday, March 22, 2015 11:16 PM

Hi,

Many items are disabled if we open Outlook in safe mode. These items are features that store their settings in the registry. We can try the following steps to see the result:

1. Close Outlook if it is running.

2. Start Registry Editor.

3. Browse to the following registry location:                                                

HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook

4. Rename the \Outlook part of this key to \Outlook-1.

5. Restart Outlook.

When you restart Outlook, a new \Outlook registry key that has default settings is created in this location.

In addition, we can also try using the Microsoft Office Configuration Analyzer Tool (OffCAT) to see if we can find any problem from the report. See:

https://support.microsoft.com/en-us/kb/2812744

If above doesn't work, we can also try testing this issue within a new windows profile. Please let me know the result.

Regards,

Steve Fan
TechNet Community Support

Thanks Steve

Renaming the Outlook Registry entry seems to have solved the problem for me.  Thanks for your expert advice.

Matt