This is a hard problem to classify as I don’t have the exact error message that Outlook gives for this. The basic problem is that when you open an attachment it puts it into a “Secure Temporary Folder”. If an attachment has the same name as another file that has already been downloaded to that folder, Outlook will append the characters (1) to the file. This number is incremented every time a similar file is opened, up to (99). Once you go over 99 it gives an error message and won’t open similar attachments.
This is a problem especially with fax servers, or scanned to e-mail documents from devices that don’t give a unique file name to their attachments. If a user gets over ninety-nine similarly named files in this folder it refuses to open any more attachments. This is a pretty easy thing to fix either manually, or with a batch file for heavy attachment users.
Step 1 – Click your start button and type “regedit”.
Step 2 – Navigate to this key: HKEY_CURRENT_USERSoftwareMicrosoftOffice12.0OutlookSecurity
Please note the 12.0 part of the above key is dependent on your Office Version. That is for Office 2007, it will be 14.0 for Office 2010. If you check out this Wikipedia article it will tell you what version number corresponds to your Office version: http://en.wikipedia.org/wiki/Microsoft_Office
Step 3 – Right the key “OutlookSecureTempFolder” and click “Modify”. Copy the value.
This will fix the problem. Make sure you get to the right registry entry as your computer might show several versions of Office in the registry.
I recommend you only use this method if you are familiar with batch scripting. You can accidentally mess other things up with a script like this.
Follow Steps 1 – 3 above and open Notepad.
Step 4 – Copy and paste the following into Notepad:
Step 5 – Paste the registry key value you copied to the second line a space after the “cd”.
Step 6 – Click File -> Save. Change the drop down menu option under the file name to “All Files” and save the file as “FixOutlookSecureTemp.bat”.
When you double click on this file it should delete everything in the proper folder and prompt before it does so. I have noticed that sometimes it won’t delete the file with the base name in this folder, giving an access denied message. This is fine, you just need less than ninety nine files of this name.
Make sure this works properly without deleting the wrong files. You can then change line 3 to “del /q *.*” and put this in your heavy user’s Startup group and solve a lot of problems automatically every time they log in.