Can't turn off FileVault (-69594)

Hi,

I have installed MacOS High Sierra on a MbP and enabled encryption with FileVault. Since I have startup issues I would like to turn off FileVault to check if this might be an issue.

I also tried via Terminal following, since turning FileVault off in System Preferences doesn't react at all:

Mac:~ user$ fdesetup status

FileVault is On.

Mac:~ user$ sudo fdesetup disable

Password:

Enter the user name:Name

Enter the password for user 'Name':

FileVault was not disabled (-69594)

I looked up the error number but couldn't find anything as many have the opposite problem.

Hope there is a reference for this number somewhere.....