Outlook 2010 Cannot Open Attachments

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Senior Member
Outlook version
Outlook 365 64 bit
Email Account
June 14, 2017

I have Outlook 2010

In my registry, I have setup to use Level1Remove so I can open attachments.

All has been working OK with opening attachments.

Windows just updated Outlook with many updates and now I cannot open any attachments. I now see one of these dialogs when I try to open or save contacts, tasks, etc.. These are contacts, tasks, etc. that I did not add any new attachments to but now receive these messages when I try to open a file or save an attachment.



I have tried a repair and SCANPST and still no luck.

Did one of the new updates (picture reflects a few of the updates) change the Level1Remove settings or did something else changed?


Thank you.

An update probably did it - - and a wild guess is that it is this one: https://support.microsoft.com/en-us...nofthesecurityupdateforoutlook2010june13,2017
as it does change blocking, per this known issue:
If an email message includes an attached email message, and the attached email message's subject line ends with an unsafe file name extension as listed in the Blocked attachments in Outlook page, the email attachment will be blocked for recipients. To fix this issue, save the email message to the computer and rename its subject line so that it does not end with an unsafe file name extension. Then, attach it to the email message to be sent.

the full list of updates is here:
Thank you Diane. After removing that update, it now works.

Do you happen to know if there may be another registry setting like Level1Remove so we do not have to remove this update on each computer that needs to open attachments.

Thank you again.

BTW - on the first screenshot - what type of attachment? It could be the subject line issue quoted in the KB article.
oh... and there are some new keys - Embedded Objects are Blocked in Outlook Tasks - there is a ready to use reg file there. There are additional keys for outlook 2016, will see if there are more for 2010 too.

DWORD: ShowOLEPackageObj
Value: 1
DWORD: AdminSecurityMode
Value: 3
DWORD: ShowLevel1Attach
Value: 1

Thank you.

The files were MSG, DOC, PDF - Ones that I think (might be wrong) always worked even without the Level1Remove setting.

Should I keep the Level1Remove and add the additional registry settings? Hopefully that will allow me to keep the patch and then just create a regedit file that I can have people run.

Because they are not blocked in messages, i would set the keys i posted. I'll see if there are any new keys for 2010 - i know there are a bunch more for 2016.
Thanks. I added the keys you noted and reinstalled the Outlook update. I now get the same message. I will remove the update and maybe there might be more keys for 2010. I appreciate your help. Thank you.
So far I haven't found a key that will allow those files but microsoft is looking into it.

On the second dialog about unsafe attachments, do the file names have two dots - filename..doc ? I was able to easily repro the first dialog but not the second one.
Thanks for the email.

I took a look at the attachment file names. All the Word files were ".doc" or ".docx". There were some "MSG" and "PDF" files that have multiple dots. For example:


There were also a few "MSG" files that had a square bracket at the end of the name. For example:


We didn't test triple dots or brackets - but i was able to repro the 'outlook not installed' error using xlxs and pdf files and microsoft is investigating. (Another MVP mentioned that 2 dots brought up a dialog when it didn't before. )

I haven't been able to repro the second dialog but it's either I'm not doing the exact same steps or you have something - reg key set probably - that I don't.
Diane. Thank you. I will go ahead and reinstall the update and try to reproduce.
I reinstalled the update and could not get it happen.

I then removed the Policy registry settings you told me about and I could reproduce it. I have a contact and now I see this at the top of the contact (names covered up). These file names did have the multiple dots.


When I then open the contact and try to Save and Close it, I then see the second dialog.

When I re-enabled the Policy registry settings you told me about, the issue concerning the second dialog did not happen again.

I then removed the update and all is working again.
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