When looking through the Communication History, you may have noticed some threads have three dots that give you an option to "Lock this thread."

https://cdn.elev.io/file/uploads/Bou3YQNOvpL_bwmecLHiFMWhQ7abkHUXh-BjyaD89XU/NSSA9mCSris6wbgx_zL099IFJMp8LLYmFSBL4-b_uW8/30-LfY.png

What happens when you lock a thread?

General (non-Admin) users will be unable to see the subject or body of the locked email.

What will that look like?

Once locked, this is how the email should look to you:

https://cdn.elev.io/file/uploads/Bou3YQNOvpL_bwmecLHiFMWhQ7abkHUXh-BjyaD89XU/fNP_DSSuU2i71ni1mT3-PmlofG3PKZc0nvpE3mfjeb4/31-lTo.png

And this is how it will look to general users:

https://cdn.elev.io/file/uploads/Bou3YQNOvpL_bwmecLHiFMWhQ7abkHUXh-BjyaD89XU/E-bSpDhqEkc3CsnQ7oY8-ygXgHPAiMojM3JpoIdw8C8/32-xzg.png

How come some threads don't have the "Lock this thread" button?

Those threads are most likely from plays that have been run and even if you locked them, any user could easily look into the play from which that email came. This defeats the purpose of locking an email.