MicrosoftEdge
Outlook delays or appears to crash when pasting HTML copied from Edge DevTools
When copying HTML code from Microsoft Edge's code viewer (DevTools) and pasting it into an Outlook email as inline text, Outlook becomes unresponsive for 10–15 seconds. This triggers a “Close or Wait” dialog, which appears to be a crash but is actually a rendering delay. The same HTML, when copied from Firefox DevTools or Notepad++, does not cause this issue. This suggests that Edge includes clipboard metadata (e.g., text/html) that causes Outlook to treat the content as active HTML, attempting to render it — including
Open a large HTML file with embedded
Expected behavior: Outlook should treat the pasted content as plain text or render it safely. Actual behavior: Outlook freezes for several seconds, prompting a crash dialog. Workaround: Copying the same content from Firefox or Notepad++ avoids the issue. Suggested fix: Strip or sanitize clipboard metadata from Edge DevTools when copying code, or improve Outlook’s handling of complex inline HTML with metadata.
HTML code copied from Edge code viewer to Outlook causes render delay.html
Example code to open in Edge browser in order to cause the issue.