Outlook 2010 is not able to open (normally) and it is in a continuous cycle of error reporting and restarting...


Florin N

I don't know what to do with MS Outlook 2010:
- to un-install
- to re-install
- to repair (somehow)?

It is not able to open (normally) and it is in a continuous cycle of error reporting and restarting...
Its outlook.pst file is over 2.5 Gb (for me, Outlook is a sort of a database with addresses, e-mails, attachments and connected various information).

The 2003 outlook did a good job until I accepted to test 2010.
2010 Outlook also, at the beginning, after importing 2003 data, worked fine, but now I don't have any access to my addresses or e-mails (just errors... when Outlook starts)

I am satisfied with Word, Excel and PowerPoint (I used so far), but worried about Outlook. (2.5Gb it is not a limit? ...or it is?)
Or, maybe you know some tricks to help me use Outlook in these conditions.

Ruchi Bisht

Provide the complete error message related to the issue.

Outlook PST file size limit will depend on the format of PST file in use. For ANSI PST format (97-2002) the file size limit is 2 GB. Unicode PST Format can store more than 2 GB of data.

If using Outlook in Safe mode as suggested by Ben eliminates the error messages then try to disable the add-ins for Outlook using the following steps and verify if it fixes the issue:

· Open Outlook > click on File > Options > Add-in

· Click on the Go button besides COM Add-ins

· Uncheck the boxes listed for the Add-ins

· Restart Outlook

Ruchi Bisht

Florin N

Ok, and thank you, Ben, it started in safe mode and downloaded the last days e-mails, but stacked in normal mode, again.

So I'll try also the other operations suggested by Ruchi Bisht (I have at least one add-on from Nitro - for PDF editing).

I'll report again the behavior of Outlook after trying this.

Florin N

Yes, in safe mode, it started... and as expected ... stacked again in normal mode.

So I unchecked the COM Add-ins (except OneNote Notes) and it stacked again in opening an e-mail from In-box.

The 335 e-mails from the server were downloading - for the second time (so you may see that another problem appeared: how to eliminate/remove the duplicates)

So far, I think that not the e-mails were the problem, and nor because I tried to read an e-mail while they were downloading.

I'll better check if the PST file format is the appropriate one, as you supposed before.

How to check this?

And how to convert my old archived e-mails, stored in that old format.pst to the new format (for large files).

Thank you again to both of you, for your advices.

Roady [MVP]

Disabling the COM add-ins didn't work as the issue probably caused by a Exchange Client Extension. Expand the dropdown list which now says COM Add-ins and select Exchange Client Extensions instead.

My guess is that the issue is caused by you having a virus scanner installed which integrates itself with Outlook. Uninstall this integration part of your virus scanner and try again; you'd still be sufficiently protected by your on-access scanner part of the virus scanner. For more details see;

As for your old/new pst-file format request see;
Am I in ANSI or Unicode format?