One of the main reasons one would use the Signal messaging app is that it has a feature in which messages sent on it will disappear after a predetermined amount of time. This means that users can have truly private conversations that will not leave any traces behind once it is all said and done.
Unfortunately for macOS users, that doesn’t appear to be the case. In a report from Motherboard, it has been discovered that Signal messages on macOS don’t completely disappear. It seems that while the messages in the app do disappear, the messages left behind in your notifications don’t.
#HEADSUP: #Security Issue in #Signal. If you are using the @signalapp desktop app for Mac, check your notifications bar; messages get copied there and they seem to persist — even if they are "disappearing" messages which have been deleted/expunged from the app. pic.twitter.com/CVVi7rfLoY
— Alec Muffett (@AlecMuffett) May 8, 2018
This was initially discovered by security researcher Alec Muffett who posted a warning to his followers. Motherboard has also managed to verify that the bug exists. While this might be annoying for some, it might be a potential deal breaker for others who use Signal for work and need absolute privacy.
That being said, it seems that this might have less to do with Signal being buggy, but rather the way Apple’s macOS handles notifications. If you still want to keep using Signal, then maybe disabling notifications on macOS might be a good idea until this has been fixed, which at the moment is unclear when that might be, but hopefully soon.