Ask again before opening an attachment

Undoing this change and re-enable the prompt before opening the attachment is only possible via the Registry.

In general, there are 2 locations which you should check, as where the change is stored depends on the file type and how it was unblocked originally.

Changing “EditFlags” in the Registry

To re-enable the prompt before opening the attachment, you’ll have to modify the “EditFlags” value for the extension in the Registry.

1. Open the Registry Editor.
2. In HKEY_CLASSES_ROOT, look for the extension that you want to change. So for a zip-file you locate;
   HKEY_CLASSES_ROOT\.zip
3. Note the (Default) value for that hive. For a zip-file this is;
   CompressedFolder
4. Now locate that description in the HKEY_CLASSES_ROOT hive. So in our example you locate;
   HKEY_CLASSES_ROOT\CompressedFolder
5. Here you'll find a key named EditFlags. This will either be a REG_BINARY or a REG_DWORD type.
6. Double click to open it and change it as follows
   • REG_BINARY
     Change the 3rd group of 2 digits to 00.
     Example:
     The value; 00 00 01 00 would then become 00 00 00 00
   • REG_DWORD
     Change the hexadecimal value of the 4th digit after 0x to 0.
     Example:
     The value 0x00210000 would then become 0x00200000

Resetting the EditFlags for zip-files via the Registry.

Internet Explorer (and some other applications)

If you disabled the “Always ask before opening this type of file” checkbox via another application, such as Internet Explorer, then it could also be that you’ll find a reference to the description value (which you determined in step 3) in the following registry location;

HKEY_CURRENT_USER\Software\Microsoft\Windows\Shell\AttachmentExecute\{0002DF01-0000-0000-C000-000000000046}

In that case, delete that value from that key or delete the AttachmentExecute value altogether to reset all the listed extensions to the configured default for your computer.