SharePoint 2013: Error loading navigation: TermStore not found - Common solutions

Introduction

In this posting, I present two causes of this problem, that I have experienced, and the solutions I implemented that resolved them.  The two causes involve minor interruptions to network connectivity and server restart.

Network Connectivity Interruptions

Problem

Your network experienced some very minor, very temporary interruptions in service.  Afterwards, some users were unable to connect to the SharePoint 2013 farm and others experienced an error in the global navigation bar:

Error loading navigation: TermStore not found (Correlation ID:...)

Note that a correlation ID appears with this error.  Checking farm health reports, a rule failure of the Security Token Service on WFE2 was found.  However, on investigation, all services were found to be running on this server, and all IIS application pools were found to be started.  Review of the WFE2 error logs found application errors involving claims authentication.  The server was up and IIS and all other services were found to be running.

Solution

• Restart the SecurityTokenClaimsApplicationPool.

Notes

• NLB was configured with WFE2 as primary and WFE1 as secondary.  Those users routed to WFE2 experienced failure connecting to the farm, while those routed to WFE1 just experienced the navigation error.  WFE2 eventually recovered partially on its own, but the navigation issue persisted.
• My sequence of troubleshooting steps for this issue:
1. Review farm health reports
2. Review server event logs
3. Check services on all farm servers
4. Check application pools on all farm servers

Server Restart

Problem

The farm servers are restarted.  Afterwards, users connecting to their site see the following error message displayed in the global navigation bar:

Error loading navigation: TermStore not found

Note that no correlation ID appears in this case for the error, unlike the earlier example.  Checking farm health reports, you find NO failure of the Security Token service on any any web front end. Checking IIS, you find that all application pools and sites have started.  Checking server services, you find that both FIM service, and the Search (OSearch) and Timer services, are in the stopped state.

Solution

• Start the Timer service.

Notes

• None