Search is returning no results because Enterprise Vault an not searhc the whole vault

[fortizz]

I am stumpted on this one. I am having issues wiht my EV i am running Version 11.0.1.3683 so version 11 CHF 4

It's working for some users but not for all. Sometimes it works and other it doesn't idon't get it and do not understand why it works at time then stops out of the blue. I have included a dtrace i took of a unsuccessful one and a successful one. 

Can anyone help me figure out whats going on. i have already tried rebuilding the index for the user. I have rebuilt the Indexing Engine so many times i can do it with my eyes closed. The latest change i made was to increase the "Search Max Folders For Specific Folder Optimisation" This worked for a little while then stopped working later that day. Is there something i am missing? Thanks

[Marcde]

Looking at the logs it seems that this is not a 64 Bit Index Volume. Can you confirm this? 

I am a bit curious about this as with your version, rebuilding an old index volume should automatically mean upgrading it.