We have started using category colours in Outlook but would like an email to retain the category when ii is sent to another user. We are using Office 2010 however have our email in the MS Cloud on Office 365 (i.e. Exchange in the cloud). All the help/information we have found so far has indicated a registry entry fixes the issue (which it does not) however I do not believe it is machine specific as you can set categories using OWA (i.e. on any machine using a web browser). Categories remain in place on my Outlook in the office, Outlook at home, OWA in a browser and OWA on my iPad so I am pretty sure its a setting within Exchange itself. We have spoke to MS but they did not fix the issue.