Hi,
What version of Outlook are you using? For versions prior to Outlook 2007 category information was stored in the following local registry:
HKCU\Software\Microsoft\Office\x.0\Outlook\Categories
Since Outlook 2007, categories are stored on the mailbox. If you want to share color categories to others, we have two choices:
1. Adding the shared mailbox as an additional mailbox and provide Reviewer permissions on the Calendar.
2. Adding the shared mailbox as an additional Exchange Account.
See the following blog article for more information:
https://blogs.technet.microsoft.com/outlooking/2012/02/03/how-to-share-color-categories-for-outlook-2010/
Hope this helps.
Regards,
Steve Fan
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