Windows January 2026 Update Causing Apps to Freeze When Saving to OneDrive or Dropbox
If you’ve noticed apps freezing when saving files to OneDrive or Dropbox after recent Windows updates, you’re not imagining it.
Microsoft has confirmed an issue introduced in January 2026 Windows updates (starting with KB5074109) that can cause applications to become unresponsive or behave unexpectedly when working with cloud-backed storage.
What does it look like in the real world?
The most obvious example so far is Microsoft Outlook, particularly where PST files are stored in OneDrive.
Users have reported:
- Outlook hanging or refusing to reopen
- Having to kill Outlook via Task Manager or reboot the device
- Sent emails not showing up in Sent Items
- Old emails re-downloading again
From the user’s perspective, Outlook just looks “broken”.
Why this is happening
While Microsoft hasn’t gone deep into the technical cause yet, the pattern is familiar:
Desktop apps don’t always cope well when their active data files live in cloud-synced folders.
When Windows updates, sync clients, and legacy app file handling collide, things can go sideways fast.
What you can do right now
There’s no proper fix yet, but a few workarounds are available:
- Do not store active PST files in OneDrive
- Move Outlook data files back to a local (non-synced) location
- Use webmail as a temporary option if available
- If this is impacting business operations, raise a case with Microsoft Support
Microsoft also suggests contacting application vendors for alternative storage methods, which, realistically, isn’t always helpful.
Who’s affected
This isn’t limited to one version of Windows. Impacted platforms include:
- Windows 11 (23H2, 24H2, 25H2)
- Windows 10 (22H2, LTSC 2019 & 2021)
- Windows Server 2019, 2022, 2025
What’s next
Microsoft says they’re working on a fix and will release an update once it’s ready. Until then, awareness and sensible file placement are your best mitigations.
If you need urgent help, Microsoft recommends contacting Microsoft Support for business.