Using classic Outlook for Windows in educational settings
The behavior matches a known Outlook issue where linked images are blocked by a specific registry setting.
In Outlook 365 classic, this occurs when the BlockHTTPimages registry value is set to 1 and the images in the message (including those in signatures) are loaded from a URL. When this value is enabled, Outlook replaces those images with the error:
The linked image cannot be displayed. The file may have been moved, renamed, or deleted. Verify that the link points to the correct file and location.
Because this is enforced at display time, it also affects messages already stored in Sent Items, which explains why older sent messages now show the same error.
To fix it, remove the BlockHTTPimages value from the registry.
- Close Outlook.
- Open Registry Editor (
regedit.exe). - Locate the key (replace
x.0with the Office version in use):- Without Group Policy:
-
HKEY_CURRENT_USER\Software\Microsoft\Office\x.0\Common
-
- With Group Policy:
-
HKEY_CURRENT_USER\Software\policies\Microsoft\Office\x.0\Common
-
- Without Group Policy:
- In that key, find the
BlockHTTPimagesDWORD with value1. - Right‑click
BlockHTTPimagesand select Delete. - Confirm deletion, then exit Registry Editor and restart Outlook.
If the value is under the Policies hive, it is likely set by Group Policy and will be recreated; in that case, an administrator must change the policy for the setting to persist.
After this change, newly viewed and newly sent messages should display the signature images correctly, provided the image URLs are valid and reachable.
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