My MacBook Pro (2021, Tahoe 26.2) is having screen issues, but only when wifi is enabled. When wifi is on, it flickers, gets horizontal lines, occasionally blacks out. But as soon as I turn the wifi off, the screen is perfectly fine. This is not happening with bluetooth, or when I connect to the internet via a cable. What is going on, what can I do?
MacBook Pro 16″
"Works in Safe mode, fails in regular mode" implies "It's something you added".
each of the others you tried, like guest user, new user, reinforces that same idea.
Consider downloading and running this little "discovery" utility, Etrecheck. It changes NOTHING. Etrecheck was developed by a senior contributor here, and uses mostly system calls and simple tests to collect often-needed information.
it contains little tests for speeds of devices, CPU utilization, memory usage, energy usage and a digest of recent problems, in one easy to use package. it does not even need to be Installed. Because less can be learned when your Mac is running great, best time to run is when your problems are actually occurring, if possible.
if you follow the directions faithfully, its report (pre-laundered of all personally-identifiable information) can be "Shared" to the System ClipBoard, then Pasted into an ‘Additional Text’ window in a reply on the forums.
Use Etrecheck Pro for free:
The amount of data you get can be daunting. If you POST your report, some Readers here are willing to look over those reports, and can provide valuable insights.
Then start a reply on the forums, click the "additional text" icon, and PASTE
"Works in Safe mode, fails in regular mode" implies "It's something you added".
each of the others you tried, like guest user, new user, reinforces that same idea.
Consider downloading and running this little "discovery" utility, Etrecheck. It changes NOTHING. Etrecheck was developed by a senior contributor here, and uses mostly system calls and simple tests to collect often-needed information.
it contains little tests for speeds of devices, CPU utilization, memory usage, energy usage and a digest of recent problems, in one easy to use package. it does not even need to be Installed. Because less can be learned when your Mac is running great, best time to run is when your problems are actually occurring, if possible.
if you follow the directions faithfully, its report (pre-laundered of all personally-identifiable information) can be "Shared" to the System ClipBoard, then Pasted into an ‘Additional Text’ window in a reply on the forums.
Use Etrecheck Pro for free:
The amount of data you get can be daunting. If you POST your report, some Readers here are willing to look over those reports, and can provide valuable insights.
Then start a reply on the forums, click the "additional text" icon, and PASTE
grythix wrote:
Follow up question: On the etrecheck report, it says I only have 20.10GB available. But in my Macbook storage it says I have 130.1GB available. That's a big discrepancy. Does that indicate a different issue, or should I just keep moving files to my external drive and hope it clears up?
Look more closely at what the EtreCheck reports shows for the "Data" volume. It shows 20GB Free and 123GB "Available". Unfortunately the "Available" value which is shown everywhere within macOS is very misleading and should be ignored, but the Free storage value which is the value you need to watch is only shown in Disk Utility or the System Profiler. The Free storage space value is the most important storage value in macOS. Even the "Used" storage value can be a bit misleading under certain conditions.
If you "Get Info" on "Macintosh HD", then you can actually compute the actual Free storage space value from the information provided:
Free space = Available space - Purgeable
As for the WiFi issues, you appear to have installed a Realtek networking driver. It does mention "WLan", so that would be my first suspect. Otherwise if a different user account had no issues, then you should try disabling your Login Items one at a time to see which one may be causing the problem.
As @Grant mentioned, you have more than one issue to deal with here. 20GB of Free storage space is the absolute bare minimum required by macOS to function without doing any work on the system since that 20GB can disappear very quickly when you're apps are actively working (foreground or background). Even with 100GB Free I see that 100GB disappear very quickly at times....as you have just discovered since 100GB of that 123GB "Available" storage is currently tied up & unusable by you. For a lot of workloads, people need to keep even more Free space....remember 100GB is the lowest you want to go. Bad things happen when you completely run out of Free storage space....such as no longer being able to delete any files to make more room due to how the APFS file system works.
WLAN Status Bar
This troublesome login Item
...is stored in the folder at:
/Library/ApplicationSupport
If you copy and paste that string into:
Finder > Go menu > Go to Folder
...it will take you to that folder.
remove the folder named:
WLAN
NB> this is NOT a standard system folder, and will not affect the built-in Wi-Fi.
These troublesome Kernel Extensions (all likely to be vestiges of a Migration from an older MacOS):
...are stored in the folder at:
/Library/Extensions
If you copy and paste that string into:
Finder > Go menu > Go to Folder
...it will take you to that folder.
Drag each of these outdated items to the Trash:
EPSONUSBPrintClass.kext - com.epson.print.kext.USBPrintClass (2.2.7)
Dropbox.kext - com.getdropbox.dropbox.kext (1.13.0 - SDK 10.14)
RtWlanU.kext - com.realtek.driver.RtWlanU (1830.15.b10 - SDK 10.9)
RtWlanU1827.kext - com.realtek.driver.RtWlanU1827 (1827.4.b25 - SDK 10.9)
After a Restart, the trash can be emptied.
the epson and dropbox items both appear to be outdated, as wells the realtek drivers.
2026-01-16 11:47:14 kdd Crash (46 times)
First occurrence: 2026-01-15 15:39:19
Details:
WD Discovery
You appear to be running WD Discovery, an app that controls WD external drives. it has crashed a LOT.
using a drive-maker's app for an external drive is troublesome.
If you are still relying on the drive-maker's software to control that drive, it may not be available AT ALL unless you are running MacOS with its Third-party Driver already installed.
examples of that situation include:
in recovery mode,
when you need to do a Time Machine restore after a disaster.
I did not see an extension for drive-maker's software, but Best Practice is to ALWAYS initialize a new drive using Disk Utility with "show all devices" active, and ERASE the DEVICE to install the MacOS Drivers.
if you did that, then just remove the WD Discovery Utility -- it is crashing.
"MacBook Pro screen problems with Wi-Fi: My MacBook Pro (2021, Tahoe 26.2) is having screen issues, but only when wifi is enabled. When wifi is on, it flickers, gets horizontal lines, occasionally blacks out. But as soon as I turn the wifi off, the screen is perfectly fine. This is not happening with bluetooth, or when I connect to the internet via a cable. What is going on, what can I do?"
-------
Troubleshooting Screen Issues when WiFi is Enabled:
Seems to be an electrical issue. It might come down to getting this serviced. But. before making that assertion, try the following... So, a few things to try here.
A. Turn Of ALL VPNs:
Do you have any VPNs enabled? If so, turn them off.
B. Try Another Network:
What happens when you try another network?
C. Add the Network Back:
Remove the network, and then add it back. Be certain you have the credentials (i.e. username and password), prior to removing it; if password protected, you'll no be able to get back in without a password.
D. Boot in Safe Mode:
See what happens when you boot in Safe Mode. In Safe Mode, login items do not open at login, and certain caches are fixed. Go here: Start Up your Mac in Safe Mode - Apple Support
E. Single-Out this User:
See what happens when you create q new Administrator user. Do you get the same issue? If not, then it is an issue pertaining to your current user. If so, then it is a system-wide issue, and you should see about getting this serviced.
"Additionally, creating a new Admin account and running through that eliminated the issue. Ideas?"
-------
It's Likely User-Related.
Reply back with report, as provided by Grant Bennet-Alder. With the report, we can go from there, seeing is anything in the report catches our eye.
your crashing is likely dies to this:
Major Issues:
Anything that appears on this list needs immediate attention.
Low disk space - This computer is running critically low on free hard drive space.
you have a 500 Gb boot disk with only 20.10 GB free. thats about four percent free,
The requirement for stable crash-free operation is about 20 percent FREE, about 100 GG
Moving stuff to the cloud is a losing proposition.
You need to move a LOT of stuff and the best way to do that is to add an additional drive, and off load your largest items (but NOT Applications).
There are additional tweaks you should make when completed, but for stability, you need more SPACE.
“Here's my etrecheck report. Thank you for all your help! For reference, this issue happened for the first time on December 19. It went away, but then came back a few days ago worse than before.”
———-
Thanks for the report.
Clearing Data:
See how much of this space is caches and other unnecessary files. Caches are created for remembrance of application use so that they open quicker, and more efficiently. Use my User Tip: How to Use Finder to Clear “System Data" on a Mac: - User Tip
At some point, you had Chrome running on your Mac. parts are still running, harvesting your data to send to google.
Chrome is particularly resource-intensive because it installs Google which renders your Mac a full time information-harvesting and -uploading "bot" for Google's purposes. Those processes can't be turned off or disabled, even if you quit the Chrome browser. Even without knowing what else is installed on that Mac it is all but assured a multitude of Google's automatically updating virus-like processes are causing your Mac to work overtime.
Get rid of it. No one needs Chrome. .
—senior contributor John Galt
Follow these removal instructions
https://support.google.com/chrome/answer/95319?hl=en&co=GENIE.Platform%3DDesktop#zippy=%2Cmac
More supporting evidence:
Follow up question: On the etrecheck report, it says I only have 20.10GB available. But in my Macbook storage it says I have 130.1GB available. That's a big discrepancy. Does that indicate a different issue, or should I just keep moving files to my external drive and hope it clears up?
Another tip is to delete text messages and emails that are no longer needed as many of them may contain attachments, photos, videos, etc. that potentially consume allot of space.
Let me know how much storage space you have recovered by writing down the before and after results.
Good luck! 👋🏼😉
Your most recent local Time machine snapshot is from jan 11, 2026. that suggest you have not connected your Time Machine drive and allowed it to complete a disk-based backup in almost a week. That seems too long to me.
if you lost your boot drive, your last backup on another drive is a week old.
¿Is that good enough?
If not, attach your backup drive more frequently and allow Time Machine to do its job.
So I did all the things you recommended (I think) - uninstalled WD Discovery, deleted WLAN, deleted the listed kernel extensions, ran time machine - and the problem continues. It's not as consistent, more intermittent. But still periodically leading to a bunch of horizontal lines then a screen blackout. I ran another EtreCheck.
you missed this one:
Launch Agents:
[Other] Wlan.Software.plist (Not signed - installed 2015-10-22)
Executable: /Library/Application Support/WLAN/StatusBarApp.app/Contents/MacOS/StatusBarApp
I may have misled you above, as:
/Library/Application Support
has a space in it, which I omitted.
So sorry
MacBook Pro screen problems with Wi-Fi
