Resolving Umbraco Examine cannot index queue items error
Introduction
Recently, while working with Umbraco 8.6.0 deployed on Azure I encountered an Examine error:
Cannot index queue items, the index is currently locked
Umbraco.Examine.UmbracoContentIndex
This is a nasty error that can cause a few problems like:
- Crashing the whole app for visitors
- Causing all kinds of back-office errors (searching, editing, examine panel overview)
- Making editors’ work impossible
- The sharp increase in log size causing additional storage costs.


Add SqlMainDomLock setting
You should follow the great thread here to get some good insights regarding Examine lock-related errors.
To resolve the issue consider adding an additional setting to your appSettings section:
<add
key="Umbraco.Core.MainDom.Lock"
value="SqlMainDomLock" />
Use Azure and Umbraco recommended setup
Umbraco’s recommended configuration can be found here and the most essential part is:
<add
key="Umbraco.Core.MainDom.Lock"
value="SqlMainDomLock" />
<add
key="Umbraco.Core.LocalTempStorage"
value="EnvironmentTemp" />
<add
key="Umbraco.Examine.LuceneDirectoryFactory"
value="Examine.LuceneEngine.Directories.SyncTempEnvDirectoryFactory, Examine" />
Rebuild Examine indexes
Once you configure/fix the app properly, you should:
- Delete all sub-folders in App_DataTEMPExamineIndexes (External, Internal, Members) with all lock files
- Restart the app
- Rebuilt indexes manually via backoffice panel (if index rebuilding does not happen automatically)