Hi guys,

We have an Umbraco installation that is used to host multiple domains.

Setup is as follows:

V7.5.4 (Nuget installed), Windows Server 2012 R2 Standard, Database: MSSQL Server 2014

I've noticed that we get quite a few of the following errors:

Provider=InternalIndexer, NodeId=-1
System.Exception: Cannot index queue items, the index is currently locked,, IndexSet: InternalIndexSet

We have experienced this in the past but it wasn't a regular occurrence. What used to be one or two errors a week has now become 20-30 a day and is something we need to resolve.

Prior to the above mentioned error appearing in the logs the following also seems to be there:

An unhandled exception occurred
System.TimeoutException: Failed to enter the lock within timeout.
   at Umbraco.Core.MainDom.Acquire()
   at Umbraco.Core.ApplicationContext.Init()
   at Umbraco.Core.CoreBootManager.CreateApplicationContext(DatabaseContext dbContext, ServiceContext serviceContext)
   at Umbraco.Core.CoreBootManager.Initialize()
   at Umbraco.Web.WebBootManager.Initialize()
   at Umbraco.Core.UmbracoApplicationBase.StartApplication(Object sender, EventArgs e)

I found that there has been a similar issue in a previous version.

We were having a different issue with chronic application shutdowns in a previous version, so we tried uninstalling a hotfix as suggested in U4-6338 because we had run out of ideas. When that didn't fix the problem we installed it back, and currently Windows is patched.

Just to confirm the hotfixes,

KB3000850 (Removed from server at one point but was reinstalled)

KB3052480 (Was always installed on the server)

Has anyone experienced similar issues in V7.5.4? If so, do you have any advise on how to resolve the issue? Any help is appreciated.