Warning When Opening attachment

Not open for further replies.


Outlook version
Outlook 2016 32 bit
Email Account
Windows 10 Pro (64 bit)/Office 2016 Business Edition (32 bit)

I have installed all Windows and Office Updates and restarted several times.

In Outlook 2016, when I try to open an email file attachment, it results in a pop up that asks/warns "You should only open attachments from a trustworthy source." It provides the options to Open, Save or Cancel. The box to “Always ask before opening this type of file” is checked and greyed out, thus, not allowing me to disable this warning.

I was able to resolve the issue for .doc files by editing the the "EditFlags" registry
Changed from 00 00 00 00
To: 00 00 01 00

However, when I tried to change for .docx, I go to: Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\ClickToRun\REGISTRY\MACHINE\Software\Classes\Word.Document.12
There is No "EditFlags" key
Can I add the "Edit Flags"? If so, could you provide me with the proper steps, as I'm very new to editing the registry.

Also, I need to perform this step for .html attachments, but am unable to locate that specific key. Do you know where its at in the registry?
Thank you very much for the recommendation

Do I add the "EditFlags" to this key:

Add it to
as reg_binary. If a dword exists for the value, rename it (i add - to the end).

With huge thanks and appreciation to Diane Poremsky above, I was able to fix all file types with the following add and changes to the registry

For .docx files, I had to add the following to this key:



“Edit Flags” REG_BINARY 00 00 01 00

For the following keys, I changed:

“Edit Flags”

Changed from 00 00 00 00

To: 00 00 01 00

00 00 00 00 displays the Open or Save dialog warning
00 00 01 00 opens the file without the warning
















For HTML Attachments


Changed EditFlags

From: 00 00 20 00

To: 00 00 01 00

Again, thanks so much to Diane's help on this!
Ah... thatkey is for 32bit office. Did the htmlfile key work in HK_classes_root?
FYI, as mentioned above, I resolved the issue, but it keeps coming back. I believe after reboots.

Thus, I have to keep:

For .docx files, I had to add the following Binary Key to this key:


“EditFlags” REG_BINARY 00 00 01 00

For .DOC files Change


from 00 00 00 00

To: 00 00 01 00
Not open for further replies.
Similar threads
Thread starter Title Forum Replies Date
Diane Poremsky Disable the Unsafe Hyperlink Warning when Opening Attachments Using Outlook 0
L Location Unsafe Warning for Links Using Outlook 1
T External email warning banner Outlook VBA and Custom Forms 0
M warning for too many appointments on a same day in Outlook Using Outlook 1
J Customize Attachement Security Warning Using Outlook 1
Diane Poremsky Meeting Location Warning Message Using Outlook 0
D Conflict warning while editing Exchange Server Administration 0
Jack Poore Outlook gives warning using GO Contracts Sync Mod Using Outlook 4
M Rule to pop a warning dialogue on certain actions Using Outlook 1
Rory Campion Not getting a warning when a shared calendar item has been updated by someone else Using Outlook 2
B How do I get a warning before deleting e-mail messages? Using Outlook 2
J Disable outlook 2010 no-subject warning Using Outlook 4
E Disable outlook 2010 no-subject warning Using Outlook 9
T Missing attachment warning Outlook VBA and Custom Forms 1
T Warning message Outlook VBA and Custom Forms 3
F No Attachment Warning - VBA Code HELP Outlook VBA and Custom Forms 1
T How to get MailItem.Body without security warning in Outlook 2010 Outlook VBA and Custom Forms 2
H How turn off outlook security warning dialog box from outlook Outlook VBA and Custom Forms 1
P Stopping that security warning Outlook VBA and Custom Forms 1
1 Warning messege Outlook VBA and Custom Forms 3
A Opening a link from an email automatically Outlook VBA and Custom Forms 0
A Opening a link from a specific sender automatically Outlook VBA and Custom Forms 4
L Opening People Outlook 2021 Using Outlook 2
U When opening shared Calendar "The set of folders cannot be opened" Using Outlook 0
KurtLass Opening Graphics Attachments in Outlook 2021 Using Outlook 0
Witzker Place cursor at opening, a user defined OL contact form Outlook VBA and Custom Forms 3
A OutLook For Mac 16.46 Comes Up In Small Window When Opening Using Outlook 4
U Disable "Always ask before opening" Dialog Using Outlook 3
Wayne Outlook locks up when opening "Manage Rules & Alerts" Using Outlook 7
B Outlook 2010 Opening Mail Attachment Using Outlook 2
D Prevent popup of "Do you want to save changes?" when closing after opening an appointment to view Outlook VBA and Custom Forms 2
H Upon opening Outlook, make my popmail inbox open instead of outlook.com inbox Using Outlook 1
J Outlook 2010 Changing events in Outlook calendar via opening file, importing CSV Using Outlook 0
L What are the risks of opening an Outlook 2016 .pst file in Outlook 2010? Using Outlook 4
D Outlook 2007 crashes when opening an email Using Outlook 2
A Outlook 2016- unable to have all subfolders expanded when opening outlook Using Outlook 11
GregS Immediate crash on opening Using Outlook 3
Diane Poremsky Error Opening Outlook and Control Panel's Mail Applet Using Outlook 0
S my vbscript button1_click code works on appointment created but not on opening an existing apntmn Outlook VBA and Custom Forms 16
J Opening Attachments - in People Using Outlook 2
Mistyfied Outlook 2016 not opening Using Outlook 2
M Update field codes when opening Outlook Template Outlook VBA and Custom Forms 2
R Outlook PST not opening Using Outlook 1
U .pst file error at opening outlook Using Outlook 1
A Problems Opening Excel from Outlook Outlook VBA and Custom Forms 3
S macro for opening attachments and printing Using Outlook 1
Z how to make OL (2007) to use custom contact form when importing / opening .VCF? Using Outlook 1
T Opening email causes "Contacting ..." message Using Outlook 1
K Outlook 2013 stuck "processing" when opening. Using Outlook 3

Similar threads