Migrating Exchange 2010 Mailbox to Office 365: Freebusy Data folder corrupt

exchange-2010exchange-migration

We have an on-premise Exchange 2010 install which we are migrating to Office 365, and I have a mailbox which is failing to migrate due to "CorruptFolderSecurityDescriptor" errors. It ended up that some of the folders in the mailbox had permissions entries for users that no longer existed, so I was able to cleanup most of the permissions issues but I still am having problems with a "Freebusy Data" folder.

However, I can not find the "Freebusy Data" folder anywhere so I am unable to fix the permissions on it. Where can I find the correct path for this folder so I can fix it?

Thanks!