After updating Mac from from macOS El Capitan to Sierra and from Sierra to High Sierra, many folks out there didn’t even realize a nasty bug decisively making connected devices useless. Thousands of MacBook Pro Retina 13-inch and 15-inch users are suffering from this severe USB failing bug that would not allow the Mac to power external medias including iPads.
We call this USB failing bug notorious bug because it makes you believe that something else is wrong not the macOS. Such notorious macOS Sierra and High Sierra inherited bug has prevented many external USB powered devices not to respond correctly. If your Mac is connected to an external display, the USB failing bug renders low external display signals or intermittent display blackening issues.
Research and findings of the notorious USB failing bug:
After many tests and active research on this notorious USB failing bug, I figured out that El Capitan does not pose this bug at all. The bug’s characteristic is to prevent required power in the aforementioned systems and low-power the external devices and thus create unreliable connection or insufficiency during transmission.
MacBook Pro Touch Bar 2016 and 2017 are not affected at all. Mostly affected Macs are 2104 and 2015 MacBook Pro Regina in both sizes: 13/15-inches.
Interestingly, the notorious USB failing bug does not have any impact on desktop Macs such as iMac or Mac Pro. Many pundits have suggested SMC reset, or resetting PRAM might fix the bug. This is absolutely a bogus advice. The bug is directly related macOS and has nothing to do with SMC or PRAM clearances.
By the time of this post writing, Apple has not yet acknowledged it and is not aware of while I tried to contact and list such. Hence the fix for this issue is going to taking some time. The bug has tremendous impact on the Macs that are powered with Intel Iris 1536MB graphics processors.
How do you find out if your Mac also house the notorious USB failing bug:
You can simply test to find out whether your Mac has this bug by connecting an iPad for a few seconds and reading what it displays at battery icon section. If your iPad tends to stay in ‘Not Charging’ mode, the bug is present in your Mac without any doubt. Try this to each of the USB ports of your Mac. Remember, this bug does not have any impact on Bluetooth or WiFi profiles. Everything else works as expected besides some reports on the mouse performance and tracking.
In regards to this bug’s extended impact, some Macs including Mac Pro and iMac are experiencing jumping mouse issues. Your mouse may tend to jump now and then while scrolling or woking in a fast pace. You may simply lose track of the mouse but it will be right back on track.
Such bugs are easy to fix by their nature but Apple needs to acknowledge it first. Sometimes, Apple doesn’t pay attention to minority bug reports hence the fixes delay. But the bug requires immediate attention since it has a greater impact in a productive computing.
This bug is also visible via System Information affecting Automatically Adjust Brightness. The Automatically Adjust Brightness happens to set as ’No’ regardless of your settings in System Preferences’ Display section in Apple Notebooks.
Some common questions related to this bug:
Does the bug impact USB ports both sides of the MacBook Pro Retina 2012 to 2015?
Ans: Yes. Many users have reported that both sides USB ports have been affected.
Does the but impact Thunderbolt ports?
Ans: Yes. The bug seems to be impacting Thunderbolt ports as well. The external display may tend to turn off at times and turn back on itself.
Does this bug impact iPhone charging while connected to the USB port?
Ans: No. Users have hardly reported that they have issues charging their iPhones. But many users have reported the issue while charging their iPads.
Does this bug have impact on Time Machine backup?
Ans: Yes. Many users have reported that their Time Machine backup did not complete. Some users also have reported that the Time Machine backup drive happens to eject at times itself.
Does this bug stop wired Apple keyboard?
Ans: Yes. Many users have reported that their wired keyboard stopped working while connected to their MacBook Pro Retina. Such cases are negligible and less audible in respect to iMac or Mac Pro. Seems like this bug has greater impact on MacBook Pro 13-inch and 15-inch released between the years 2012 and 2015.
Does this bug go away if I reset PRAM or SMC?
Ans: No. Nothing to do with PRAM and SMC. This bug is macOS related but that is not addressing uninterrupted power balance back and forth while external medias are connected. Hence SMC reset or PRAM reset will not resolve this issue. This bug requires an immediate Apple attention and future update of the bug fixes.
So, if the but is not fixable by SMC or PRAM reset, how to get rid of it?
Ans: Contribute to a greater voice. Participate in the comments and raise voice as loud as possible so that Apple steps down and acknowledges the flaw in the macOS so works harder to release a bug fix update.