Crawls in Sharepoint stop

This issue took a long time to drill down into the root cause.

Symptoms

1. Sharepoint crawls of searchable content were not being run. The scheduler was working but when the crawl was initiated, nothing happened. The ‘time of next incremental crawl’ was incremented, though.

2. When attempting to view some areas within Sharepoint Admin an error was returned: “user or domain not found”.

Solution

The issue was actually that the Permissions of one particular Sharepoint Service referenced accounts that had since been removed or renamed. The only way to solve the problem was to reinstate, or un-rename, the account in question.

TIP: never assign permissions for a Sharepoint Service to a user account or Administrator. Always use dedicated service accounts.

Details

These articles helped me get to the root of the problem.

First, to find the actual Sharepoint Service that was impacted by the problem I followed these steps. For this specific case I determined that the problem lay in the Userprofile service.

Next, this article directed me to the Permissions under Manage Service Applications where I then saw the offending accounts.