While working on a Cutover migration for Office 365 I ran into an error with the default search folders in Outlook. The data had migrated successfully. The Outlook profiles were recreated. Mail was flowing. However, when clicking on the Unread Mail folder it resulted in the following error.

This same error occurred when clicking on other search folders; such as Categorized Mail, or, Large Mail.

Thankfully the fix was incredibly simple.
What exactly are Search Folders?
Search Folders are a virtual folder that contains items based on criteria you specify. For a full list of all available search criteria click the Folder tab >> New Search Folder button.

This will display a dialog allowing you to create a Search Folder from twelve different templates. Each template requires user input to define what the Search Folder should display. For example, Large Mail requires you to set the threshold for what you consider large. This number is configured in kilobytes and defaults to 100 KB. If we kept the default value anything over 100 kilobytes will be displayed in this folder.

In addition, this dialog grants you the option to create a custom Search Folder. You can specify countless different criteria on these three tabs creating an endless set of combinations.

But what about the error?
Fix “The attempted operation failed. An object could not be found.”
To fix this error right click on the search folder in question–in our case Unread Mail–select Customize This Search Folder from the context menu.

This will bring up the Customize dialog box. You may notice the “Mail from these folders…” is blank. It should contain a value. Click the Browse button.

In the Select Folders dialog box, pick your top-level folder. In our example, this is my email address. Make sure the Search subfolders checkbox is selected. Click Ok twice.

Be sure to repeat this for all search folders. In our example, we repeated this for Larger Than 100 KB and Categorized Mail.
Conclusion
Search Folders are a powerful tool. They allow you to easily find and manage your email. For more information on Search Folders, check this link.
We’d also like to hear from you. Did you have a similar experience with Search Folders when performing a Cutover migration in Office 365?
Googled this issue and a lot of “Outlook Tools” came first, waisting time on “solutions” and “workaround” and concluding “PST Corruption tha requires a tool” (theirs) to fix this… Glad I landed on your page and what a simple solution. This happens to me when migrate Outlook Spanish to Outlook English.
Easy, corrected the problem. Done! Great Advice! Thank You!
Thanks for posting this! It solved my problem. I only wish I had seen it before I tried multiple Office repairs. I was seeing this problem on Office 365/Office 2016. Not sure why the search folders get lost, but with this info it was easy to fix. Thanks!
This was so great, thanks
Thank you! I did a search and tried your article first. It was exactly the problem I was having. I was able to quickly and easily fix my problem. So often I do a search and read dozens of the search results that seem to be my exact problem and I never find a solution. To find a well written and explained solution on the first article I tried … well … I was glad I was sitting down.
Thanks again!
Glad I was able to help Paul! Thank you for your comment. It means a lot! I hope you like the rest of the site.
Gareth, thanks for posting the fix – I found it after re-installing Office, iCloud and was about to rebuild my profile!