I noticed this warning in the Experience Editor of a Coveo Hive search page, specifically on the search interface:
Error when serializing the property "RankingState". (Exception has been thrown by the target of an invocation.)
I immediately checked the Sitecore logs and found a long winded exception chain. The head exception was of course, “Exception has been thrown by the target of an invocation“. Many nested exceptions below that, at the very bottom of the chain, I found this error:
Exception: System.InvalidOperationException Message: Cannot use DataAdapterProvider as xDB is disabled. Source: Sitecore.Analytics.DataAccess at Sitecore.Analytics.DataAccess.DataAdapterProvider..ctor() at Sitecore.Analytics.Data.DataAccess.MongoDb.MongoDbDataAdapterProvider..ctor(Func`2 driverFactory)
Researching that error, I found that the problem was my settings in the Sitecore.Xdb.config file (under App_Config/Include). I had XDB disabled, but not XDB.Tracking disabled. I disabled XDB.Tracking and the warning went away. I assume if you have XDB disabled, you should also disable tracking because it relies on XDB. Just thought I’d quickly post this problem and solution as I continue working with Coveo Hive.