It appears that the May 14, 2019 Security Update KB4464549 https://support.microsoft.com/en-us/help/4464549/description-of-the-security-update-for-sharepoint-enterprise-server breaks SharePoint Search. A possible workaround is to load the portal with http:// instead of https:// and search will work. We will update this Blog post with any additional news and workarounds that we find.
It turns out that after the patch was installed either the SharePoint Configuration Wizard was not run or did not successfully complete. To check if an update was successful:
- Start SharePoint Central Administration.
- Check Upgrade Status.
- The last updated date should be later than the 5/14/2019 patch installation date.
If it doesn't show a date after you've installed the 5/14/2019 security update, run the SharePoint Configuration Wizard and make sure it sucessfully completes. Go back into the Update Status page and verify that the status is Succeeded with a date after the 5/14/2019 patch installation date. After you've verified the update succeeded, perform an Index Reset and a full Crawl and Search should work again.
- Perform a Search Index Reset. In Central Administration, click on Application Management, Manage Service Applications, Search Service Application, Index Reset, Reset Now.
- Perform a Full Crawl. Click on Content Sources, Click on Local SharePoint sites, Start Full Crawl.
Test Search - it should work again.