Fix for ASP.NET 4.0.30319.0 - 3005 Event message: An unhandled exception has occurred on Exchange 2013

I noticed after installing Windows Updates the following warning in the Application Event log of all Exchange 2013 SP1 servers (abbreviated for clarity):

Event 1309, ASP.NET 4.0.30319.0

Log Name:      Application
Source:        ASP.NET 4.0.30319.0
Date:          5/3/2014 9:31:25 AM
Event ID:      1309
Task Category: Web Event
Level:         Warning
Keywords:      Classic
User:          N/A
Computer:      EX2013-1.contoso.com
Description:
Event code: 3005
Event message: An unhandled exception has occurred.
Event time: 5/3/2014 9:31:25 AM
Event time (UTC): 5/3/2014 4:31:25 PM
Event ID: 20e50da04e9745e1a73bf21fa1dbb509
Event sequence: 2
Event occurrence: 1
Event detail code: 0

Application information:
    Application domain: /LM/W3SVC/3/ROOT/owa-3-130436082719776031
    Trust level: Full
    Application Virtual Path: /owa
    Application Path: C:\Program Files\Microsoft\Exchange Server\V15\ClientAccess\owa\
    Machine name: EX2013-1

Process information:
    Process ID: 6068
    Process name: w3wp.exe
    Account name: NT AUTHORITY\SYSTEM

Exception information:
    Exception type: MapiExceptionIllegalCrossServerConnection
    Exception message: MapiExceptionIllegalCrossServerConnection: Monitoring mailbox [] with application ID [Client=OWA] is not allowed to make cross-server calls from [EX2013-1.contoso.com] to [EX2013-2.contoso.com]
   at Microsoft.Mapi.CrossServerDiagnostics.BlockCrossServerCall(ExRpcConnectionInfo connectionInfo, String mailboxDescription)
   ...
   at Microsoft.Exchange.Data.Storage.MailboxSession.ForceOpen(MapiStore linkedStore, Boolean unifiedSession)

Request information:
    Request URL: https://localhost:444/owa/proxylogon.owa
    Request path: /owa/proxylogon.owa
    User host address: ::1
    User: contoso\SM_ce56bab178eb42fda
    Is authenticated: True
    Authentication Type: Kerberos
    Thread account name: NT AUTHORITY\SYSTEM

Thread information:
    Thread ID: 15
    Thread account name: NT AUTHORITY\SYSTEM
    Is impersonating: False
    Stack trace:    at Microsoft.Mapi.CrossServerDiagnostics.BlockCrossServerCall(ExRpcConnectionInfo connectionInfo, String mailboxDescription)
   ...
   at Microsoft.Exchange.Data.Storage.MailboxSession.ForceOpen(MapiStore linkedStore, Boolean unifiedSession)

The text highlighted above steered me toward the Exchange Health Monitoring Mailboxes, so I ran Get-Mailbox -Monitoring and got the following results:

Name                      Alias                ServerName       ProhibitSendQuota
----                      -----                ----------       -----------------
HealthMailbox9a621ae8e... HealthMailbox9a62... ex2013-2         Unlimited
WARNING: The object contoso.com/Microsoft Exchange System Objects/Monitoring
Mailboxes/HealthMailbox9a621ae8e6f341638c0c2161affa7645 has been corrupted, and it's in an inconsistent
 state. The following validation errors happened:
WARNING: Database is mandatory on UserMailbox.
WARNING: Database is mandatory on UserMailbox.
HealthMailbox1cd7a25f1... HealthMailbox1cd7... ex2013-2         Unlimited
HealthMailboxde79dfaa0... HealthMailboxde79... ex2013-2         Unlimited
WARNING: The object contoso.com/Microsoft Exchange System Objects/Monitoring
Mailboxes/HealthMailboxde79dfaa09604ffd8578527c2d3ffab1 has been corrupted, and it's in an inconsistent
 state. The following validation errors happened:
WARNING: Database is mandatory on UserMailbox.
WARNING: Database is mandatory on UserMailbox.
HealthMailbox5e5bf093c... HealthMailbox5e5b... ex2013-2         Unlimited
HealthMailbox79f8d5d0e... HealthMailbox79f8... ex2013-2         Unlimited
WARNING: The object contoso.com/Microsoft Exchange System Objects/Monitoring
Mailboxes/HealthMailbox79f8d5d0e02443d2a6acdc60bd0a026e has been corrupted, and it's in an inconsistent
 state. The following validation errors happened:
WARNING: Database is mandatory on UserMailbox.
WARNING: Database is mandatory on UserMailbox.
HealthMailbox693969aae... HealthMailbox6939... ex2013-2         Unlimited
HealthMailboxab01377ba... HealthMailboxab01... ex2013-2         Unlimited
WARNING: The object contoso.com/Microsoft Exchange System Objects/Monitoring
Mailboxes/HealthMailboxab01377bae994825ba08d083552e196e has been corrupted, and it's in an inconsistent
 state. The following validation errors happened:
WARNING: Database is mandatory on UserMailbox.
WARNING: Database is mandatory on UserMailbox.
HealthMailbox7561b21db... HealthMailbox7561... ex2013-2         Unlimited
WARNING: The object contoso.com/Microsoft Exchange System Objects/Monitoring
Mailboxes/HealthMailbox7561b21db2c642778177f4ab0a2be350 has been corrupted, and it's in an inconsistent
 state. The following validation errors happened:
WARNING: Database is mandatory on UserMailbox.
WARNING: Database is mandatory on UserMailbox.
HealthMailboxb337fe270... HealthMailboxb337... ex2013-2         Unlimited
HealthMailboxfd8b0f99f... HealthMailboxfd8b... ex2013-2         Unlimited
HealthMailbox739cff7e6... HealthMailbox739c... ex2013-2         Unlimited
HealthMailboxd8337c5a1... HealthMailboxd833... ex2013-2         Unlimited
HealthMailboxa990ff65c... HealthMailboxa990... ex2013-1         Unlimited
HealthMailbox91e52135c... HealthMailbox91e5... ex2013-1         Unlimited
HealthMailboxf351943c2... HealthMailboxf351... ex2013-1         Unlimited
HealthMailbox23eb6e495... HealthMailbox23eb... ex2013-1         Unlimited
HealthMailbox1821ba284... HealthMailbox1821... ex2013-2         Unlimited

Besides the fact that some of the Health Mailboxes were missing the mandatory Database parameter, there were far too many Health Mailboxes. The easy way to correct this is to delete all the Exchange Health Mailboxes and recreate them.

Open Active Directory Users and Computers and enable Advanced View. The Health Mailboxes are located under Microsoft Exchange System Objects \ Monitoring Mailboxes. Select all of the HealthMailbox objects, delete them, and replicate AD.

Microsoft Exchange System Objects \ Monitoring Mailboxes

Now that the Exchange Health Mailboxes are gone, restart the Microsoft Exchange Health Manager service on all Exchange 2013 servers to recreate the necessary Exchange Health Mailboxes:

[PS] C:\>Restart-Service MSExchangeHM

Replicate AD again and you will see the new Exchange Health Mailboxes in the Exchange Management Shell and ADUC:

[PS] C:\>Get-Mailbox -Monitoring

Name Alias ServerName ProhibitSendQuota
---- ----- ---------- -----------------
HealthMailbox7b3ef7a60... HealthMailbox7b3e... ex2013-1 Unlimited
HealthMailbox312d14677... HealthMailbox312d... ex2013-2 Unlimited
HealthMailbox1aec3204b... HealthMailbox1aec... ex2013-1 Unlimited
HealthMailboxa04a8b769... HealthMailboxa04a... ex2013-2 Unlimited
HealthMailbox04e954fc9... HealthMailbox04e9... ex2013-1 Unlimited
HealthMailboxd20957258... HealthMailboxd209... ex2013-2 Unlimited

Recreated Health Mailboxes

Two monitoring mailboxes are created for each mailbox database in your organization: one for monitoring the health of site mailboxes and one for monitoring the health of public folders. That should resolve the ASP.NET 4.0.30319.0 warnings.