File links in Word and Excel suddenly do nothing. What should I check?

If it reproduces across users and fresh documents, I’d treat the Office link-launch path as the main suspect, not the files themselves. The fact that Office resolves the path but never tries to start the target is a useful clue.

On one test device, check whether the Office protocol handler runs correctly and try an Office repair before rolling back. Keep a before-and-after trace so you can tell whether the repair changes the launch behavior.

One reported workaround was to reset the affected file-type associations, especially for common document types. That’s worth testing on a single machine, but I’d be cautious about registry edits from an unverified comment. Export the relevant settings first, and don’t apply a broad association change across devices until it’s confirmed.

Could be a build regression, but the symptoms alone don’t prove that. Compare an affected machine with one that still works, including the exact Office build and update channel, then test the same file link after an Office repair or on a controlled rollback. That should help separate a version issue from a local configuration problem.

Since the link targets include both local and network files, and opening those files directly works, I wouldn’t start by changing permissions or rebuilding the files. If a target is cloud-managed, checking whether it is actually downloaded is still a quick check, but it seems less likely to explain every kind of link failing.