While deploying an Exchange server, you may run into the following error during setup, which will block the installation from continuing.
[07/01/2020] ErrorRecord: Cannot find an overload for "CompareTo" and the argument count: "1". [07/01/2020] ErrorRecord: System.Management.Automation.MethodException: Cannot find an overload for "CompareTo" and the argument count: "1".
This error is definitely cryptic. Thankfully the Exchange Setup Logs (located at “C:\ExchangeSetupLogs\ExchangeSetup.txt”) is excellent at providing more clues when troubleshooting.
In our case, the logs identified that setup was trying to process the Offline Address Book (“OAB”) at the time of the error. The error occurred during a function that contained OAB-related PowerShell commands, including Get-OfflineAddressBook, Get-OabVirtualDirectory, and Set-OfflineAddressBook. So, this was the logical place to continue troubleshooting.
From another Exchange Server, we ran the PowerShell command Get-OfflineAddressBook, and strangely, three address books were returned.
C:\> Get-OfflineAddressBook | Format-List Name Name: Default Offline Address List Name: Default Offline Address List (Ex2013) Name: Default Offline Address List (Ex2013) CNF:3e4b413a-e5d6-4371-8541-defecb812f98
The returned results were strange.
- Default Offline Address List is an OAB from a legacy Exchange installation (Exchange 2010 and earlier) and is common to see in an Exchange environment.
- Default Offline Address List (Ex2013) is present whenever an Exchange 2013 or 2016 server is installed into a legacy Exchange environment. This address list is standard, and it is common to see both this OAB and the first OAB coexisting in mixed Exchange environments.
- Default Offline Address List (Ex2013)CNF:<GUID>, is an address list I had never seen before.
Default Offline Address List (Ex2013)CNF:<GUID> being an unknown quickly became the focus of our investigation.
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