Outlook might freeze when saving files to OneDrive

"According to Microsoft, after installing the January 13 update, "some applications might become unresponsive or experience unexpected errors when opening files from or saving files to cloud-backed storage, such as OneDrive or Dropbox." One application is Outlook, which, when combined with a PST (Personal Storage Table) file on OneDrive, "might become unresponsive and fail to reopen unless its process is terminated in Task Manager, or the system is restarted." Sent emails might also fail to appear."

"The workaround for Outlook is to move the PST file out of OneDrive. Putting a PST file in OneDrive is generally not recommended except for backup purposes, though there are plenty of scenarios where users or administrators do so, and changing a workflow due to a bug introduced by an update is not ideal."

"The advice Microsoft dished out to users experiencing the glitch is to "contact the application developer for possible alternative methods of accessing the files." Microsoft also suggested users left staring at a frozen Outlook could use webmail "if supported by your email provider." In the meantime, it added: "We are working on releasing a resolution for this issue as soon as possible. We will provide an update when more information is available.""

After the January 13 Windows update, some applications become unresponsive or produce errors when opening or saving files to cloud-backed storage such as OneDrive or Dropbox. Outlook combined with a PST file stored on OneDrive can freeze and fail to reopen unless its process is terminated or the system is restarted, and sent emails might not appear. The temporary workaround is to move PST files out of OneDrive because storing PSTs in OneDrive is generally only recommended for backups. Users are advised to contact application developers or use webmail, and a resolution is being developed.

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