Reinstall Office 365 on a Windows 10 laptop

Frank Mayer 21 Reputation points
2026-07-13T20:25:41.2233333+00:00

I had a technician attempt to fix my Office 365 and the guy really made a mess and really screwed up Outlook. This was when Google switched to multi factor authentication. So, he change from the default which I can't remember to IMAP/SMTP which leaves everything on the default Google account. Outlook now does not show when I send a response to a message (I remember an arrow indicating a response was sent) and if I open and respond to an email, I cannot move that email to a saved folder because it has been changed. Sometimes when I attempt to paste into a Word document, I run into an error indicating that there was an error but I can re-paste and most of the time it works.

I have a number of add-in on both Outlook and Word and I will never know how to get them back. It's been at least 5 years that I have use Office 365.

I need to know what kind of setting I need to save so once the re-install takes place I can make the updates. Of course this can only be done on a weekend since I use Office 365 in a "production" environment during the week. Plus if I run into issues that I can't solve, I certainly would like a support telephone number for assistance.

Regards.
[removed PII]

Microsoft 365 and Office | Other
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Answer accepted by question author
Kai-H 26,950 Reputation points Microsoft External Staff Moderator
2026-07-15T07:29:46.9333333+00:00

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Hi, Frank Mayer

A reinstall may not fix Outlook because the damaged account settings and profile can remain after Office is removed. Gmail should normally be added through Outlook’s automatic sign-in, which supports Google’s multifactor authentication, rather than by manually entering IMAP/SMTP settings.

Here are some suggestions you can try:

Before removing anything, take screenshots of File > Account Settings > Account Settings, File > Options > Add-ins, signatures, rules, and customized views. Copy any PST files, templates, macros, and the Signatures folder under %appdata%\Microsoft. Also save the installers and licence details for third-party add-ins, as COM add-ins usually need reinstalling.

Try Settings > Apps > Microsoft 365 > Modify > Online Repair first. For the missing reply arrows, use View > Reset View, or View Settings > Columns and add Icon. These fixes have restored the indicators in classic Outlook.

If Outlook remains unreliable, create a fresh profile through Control Panel > Mail > Show Profiles > Add. Add the Gmail address normally and complete the Google sign-in window. Do not manually choose IMAP unless automatic setup fails.

If a full reinstall is still needed, use the official Office uninstall troubleshooter, restart, then reinstall from the Microsoft account that owns the subscription.

For assistance, use Microsoft Contact Support and request chat or a callback. Avoid telephone numbers found through advertisements or unofficial websites.

Thank you for your patience in reading, I hope this information has been helpful to you. 

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  1. Frank Mayer 21 Reputation points
    2026-07-15T13:26:47.8933333+00:00

    Thanks very much. I will give this a try later this week or next. I am also installing a new system backup software in the event something goes wrong. I can get back to the beginning.

    Best,
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