Spotlight doesn't work well, search in Mail doesn't work quite

Hello m1ghaI,

For this type of issue you may wish to try rebuilding the Spotlight index. This page can help out with that process: Rebuild the Spotlight index on your Mac - Apple Support

Rebuild the Spotlight index

1. Choose Apple menu  > System Preferences, then click Spotlight.

2. Click the Privacy tab.

3. Drag the disk or folder that you want to index again to the list of locations that Spotlight is prevented from searching. Or click the add button (+) and select the disk or folder to add.

You can add an item to the Privacy tab only if you have ownership permissions for that item. To learn about permissions, choose Help from the Finder menu bar, then search for “permissions.”

4. From the same list of locations, select the disk or folder that you just added. Then click the remove button (–) to remove it from the list.

5. Quit System Preferences. Spotlight will reindex the contents of the disk or folder. This can take some time, depending on the amount of information being indexed.

With regards to searching in Mail, the steps here to rebuild mailboxes may help: Rebuild mailboxes in Mail on Mac - Apple Support

1. In the Mail app  on your Mac, select a mailbox in the sidebar.

2. Choose Mailbox > Rebuild.

When you rebuild mailboxes for IMAP or Exchange accounts, messages and attachments stored on your Mac are discarded, and then downloaded again from the mail server to your Mac. Your mailbox appears empty until the download is complete.

Cheers.

Thanks for the update, m1ghaI.

Since rebuilding Spotlight and your mailboxes didn’t resolve the issue, we’d like to isolate the issue a bit.

How to use safe mode on your Mac - Apple Support -- Restart your Mac in safe mode and see if Spotlight works as expected. Once you’ve finished testing, restart your Mac normally to exit safe mode. We also want you to be aware that restarting in safe mode may take a bit longer than usual since it prevents some software from loading and does a check of your startup disk.

If the issue didn’t happen while your Mac was in safe mode, test the issue again after a normal restart.

Please let us know the results when you're able.

All the best.

Hey m1ghaI,

Thanks for informing us that you’d also tested in a new user account since that was our next steps to try to isolate the issue.

If you do find the time to reinstall macOS, we highly recommend it since the issue occurs in both safe mode and a new user account. Since it appears you know the steps to reinstall macOS, we’ll leave this here for others who may find your post and needs this information: How to reinstall macOS - Apple Support

Also, if you’d rather, we recommend contacting Apple Support to look into this issue further with you: Get Support.

Take care.