“Status: Failed” running New-PublicFolderMigrationRequest on Exchange 2013

Issue: when verifying your public folder migration from Exchange 2007/2010 to 2013 you get a ‘status failed’.

Background:
In order to check the status of the migration request run the following commands:
Get-PublicFolderMigrationRequest
More verbose detail:
Get-PublicFolderMigrationRequest | Get-PublicFolderMigrationRequestStatistics -IncludeReport | Format-List

Your results may contain the following:
Report: Fatal error DataValidationException has occurred
Status : Failed
Error: Property expression “Client Lunch Schedule” isn’t valid. Valid values are:
Strings formed with characters from A to Z (uppercase or lowercase), digits from 0 to 9, !, #, $, %, &, ‘, *, +, -, /, =, ?, ^, _, `, {, |, } or ~. One or more periods may be embedded in an alias, but each period should be preceded and followed by at least one of the other characters. Unicode characters from U+00A1 to U+00FF are also valid in an alias, but they will be mapped to a best-fit US-ASCII string in the e-mail address, which is generated from such an alias.

Cause: Some of your public folders have improperly formatted alias’s.

Resolution:
1) Open the public folder management tool in Exchange Management Console > Toolbox

2) Review each mail enabled public folder (mail enabled public folders have the large envelope icon):
-Select the parent folder in the left pane, right click and click properties.
-Review the “Exchange General” Tab, specifically the alias field.
-Alias must not contain any improper characters like spaces and symbols.
-Remove or replace the improper characters on each mail enabled public folder.

Next you can continue your migration by re-running the migration command that you ran previously:

Exchange 2007: New-PublicFolderMigrationRequest -SourceDatabase (Get-PublicFolderDatabase -Server <Source server name>) -CSVData (Get-Content <Folder to mailbox map path> -Encoding Byte) -BadItemLimit $BadItemLimitCount

Exchange 2010: New-PublicFolderMigrationRequest -SourceDatabase (Get-PublicFolderDatabase -Server <Source server name>) -CSVData (Get-Content <Folder to mailbox map path> -Encoding Byte)

Next you will need to remove the failed public folder migration request.