Does iMac encryption take very long?

Frank, the drive on your iMac is already encrypted. If you have external drives with information you think someone might steal then encrypting those offer extra protection. Personally, I never encrypt anything because no one else has access to my Macs.

I always turn FileVault on. If my Mac is ever lost or stolen, my data is completely secure and inaccessible. Also, there is no performance penalty or other issue. But be aware of the following:

If you lose both your account password and your FileVault recovery key, you won't be able to log in to your Mac or access the data on your startup disk.

Turning FileVault on used to take quite awhile (but you could use your Mac normally while it encrypted). Now on newer Macs it is virtually instantaneous since your drive is already encrypted. See the following from Encrypt Mac data with FileVault - Apple Support

Note: If you have an iMac Pro or another Mac with an Apple T2 Security Chip, the data on your drive is already encrypted automatically. However, turning on FileVault provides further protection by requiring your login password to decrypt your data.

Also see: Use FileVault to encrypt the startup disk on your Mac - Apple Support

On your internal drive you can turn on or off Filevault. Turning on with M1 Mac is instant. With Intel Mac will take several minutes. You can format external drives to include encryption which will also be done quickly.

frank_the_snake_master_01 wrote:

FoxFifth

Thank you for this info I do not take my iMac anywere.

Thank you

Frank

I have a MacBook Pro and occasionally take it out so chance of theft is increased. But I also feel a bit safer in situation of some potential failure where it won't start and needs to go in for repair (and theft from my house is extremely unlikely but not an impossibility).

And it doesn't cost me anything (i.e., no downside).

frank_the_snake_master_01 wrote:

dialabrain

Thank you buddy your always there for me? How are you doing?

You're welcome. I'm good. Hope you are as well.

FoxFifth wrote:

And it doesn't cost me anything (i.e., no downside).

FWIW, there is a downside for me. FileVault disables automatic login.