In Exchange 2010, you can place a mailbox on retention hold or legal hold. Both holds serve a different purpose. It's important to understand the functionality provided by both.
Retention Hold: A...
Updated Jul 01, 2019
Version 2.0
Blog Post
Something that everyone here should know, however, is that Outlook 2010 will only show these options if it is installed as a stand-alone install or as part of the Office 2010 Professional Plus bundle. All Policy and Archive options are disabled if you install as any other bundle including Standard, Small Business, Home & Student, or Professional.
I spent the past two weeks on the phone with Microsoft Product Support painstakingly troubleshooting this because nobody seemed to know about this limitation! It's buried as a footnote on the Office product comparison chart.