What is this green symbol on the touch bar?

Question

I've seen this green symbol on the touch bar of a MacBook Pro, as shown in the image below. I have no idea what it could mean or what it signifies.

Some details about it:

• It only comes on when the touch bar is "asleep", in that there isn't anything else displayed on the touch bar. Activating the touch bar makes it go away.
• It appears to be three toned.
• I cannot interact with it. Touching it does nothing.
• Sometimes it flashes. The rate of flashing is variable and doesn't seem tied to anything sensible that I can find.
• It is right next to the power button at the end of the touch bar.

Some details about the computer:

• 13-inch, 2018 MacbookPro
• Running macOS Catalina, 10.15.3

Any ideas?

Answer 1

This is no icon or a symbol but rather a hardware error.

The greeninsh flashing rectangle next to the TouchID button has been recognized as sign of a faulty Touch Bar in several cases:

Video:

• Guide to AppleCare for Mac & Overnight Shipping (title is misleading!)

Online Forums:

• Flashing Touch Bar rectangle (text only)
• 2017 MBP touchbar flashing issues (text, the pics and videos linked in the thread don't work for me)
• little white box on touch bar when macbook pro is asleep. anyone know what it is? (the issue was reinterpreted as a "feature": It’s your sleep notification light)

Answer 2

That issue can be a hardware issue like the logic board, top case or the connectors that link the two, but it also can be a sign that the firmware and T2 chip needs to be revived or restored. The software reload can be done at home or anywhere another Mac can be obtained to service the touch-bar Mac.

• MBP Touch bar control strip gone
• Revive or restore Mac firmware in Apple Configurator 2

Back up your data and test well so you know the backup is complete and good before you either seek repair or attempt to fix this. One of the options above will wipe your data intentionally.

To fix this, we use another Mac and Apple Configurator 2 to reload the non Mac firmware using an iOS-like DFU process described above. Your data will not be recoverable if service decides this is needed or swaps parts. Same if you attempt to revive things - this makes all data unrecoverable if it fails or if it succeeds. Be prepared to reinstall macOS and then load your data, Apps, settings from backup if you start this test. The test will determine if you just needed to reload the software that runs the T2 chip and Secure Enclave and BridgeOS or there’s an actual hardware failure. So far, we have seen software resolve this specific glitch in all cases so hopefully you don’t need a repair.