While upgrading to version 4.6, the upgrade does not complete after several hours.  If it does complete, after logging in, you see no layers or imag templates.  And you will see errors like:

"System Error - ComponentActivator: could not instantiate Uni.Appliance.PersistenceLayer.Session.SessionScope"

Or:

(could not execute query
[ select folder0_.fldId as fldId35_, folder0_.fldType as fldType35_, folder0_.fldParent as fldParent35_, ...

Or

could not execute query
[ SELECT this_.ssName as ssName49_0_, this_.ssDataType as ssDataType49_0_, this_.ssValue as ...

You may also see the error:

1.SCRIPT5022: Unhandled Error in Silverlight Application An unexpected system error occurred.  Retry the operation or contact technical support.
  о System.Runtime.CompilerServices.AsyncServices.<ThrowAsync>b__0(Object state)
 

You must reduce the number of virtual CPUs on the ELM.  The ELM is initially deployed with 4 CPUs and 8GB of RAM, and this is the configuration we test with.  We do not support diverging from this.  Roll back to your VM snapshot, if available, reduce the number of CPUs to 4, boot up, and re-run the upgrade.  

If you do not have a snapshot, shutdown, reduce the number of CPUs to 4, boot back up, and test your environment.  You may need to open a case with Technical Support to recover from an unfinished upgrade.

 

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Problem Cause

When the ELM boots up, in order to maximize multithreading efficiency, each Connector will spawn one process per detected CPU core.  In 4.6, with the addition of the new Hyper-V connector, we now have six connectors.  With the default 4 CPU cores, making 4 processes per connector, you remain well within the limits of the number of connections to the configuration database allowed.  However, if you have manually increased the number of CPUs, then the extra Connector processes automatically spawned is likely to exceed that limit.  8 CPUs was not a noticeable problem in 4.5, because there were only 5 connectors, so the limit of connections was only rarely exceeded.  In 4.6, it is immediately exceeded on bootup, breaking both the upgrade and subsequent ELM operation if the upgrade eventually succeeds.