No Video 2018 15" MacBook Pro, eGPU and LG 5K Display

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Stempnakowski

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  • Joined: Thu Sep 17, 2020 7:49 pm
  • Real Name: David Stempnakowski

No Video 2018 15" MacBook Pro, eGPU and LG 5K Display

PostThu Sep 17, 2020 8:13 pm

I bought a BM eGPU for my 2018 15" MBP (only 4GB Radeon built-in). The MBP is running macOS 10.15.6, has 32GB RAM, and is connected via Thunderbolt 3 to an LG 5K ultrafine monitor. I got the eGPU and so the connection is Mac -> eGPU -> Lg 5K. The only way I can get video on the LG display after rebooting the Mac is to zap the PRAM. If I don't, I can see the Apple logo and even the logon, but once I select a user the screen goes black and nothing. I'm using the MacBook in clamshell mode.

I've booted in safe mode and same thing. I've created a new user, same issue. I connected it to an HP Windows 10 Pro laptop which wouldn't even recognize it.

I'm trying to determine if the issue is with the Mac, the OS, or the eGPU. I have a new Thunderbolt 3 cable ordered to try and replace the one that came with the eGPU and see if this works.

If I boot the Mac, display open, and zap the PRAM everything works fine. If I should have to reboot, then I can get as far as entering the user name and password, then the screen blacks out and nothing but the fans spinning up on the MBP. If I boot with the MBP display open, I can get to the desktop, but no display on the LG but I can see USB-C devices connected to the LG display. I can see the eGPU menubar item but it says no eGPU connected.

Open to suggestions on how to proceed to troubleshoot. I even, briefly, considered installing Mac OS 11 developer beta, but I prefer to wait for the GM release for this machine. I have a 2015 MBP for development that is running Big Sur, but it only has Thunderbolt 2.

Thank you for your time.

Update: So a replacement Thunderbolt cable made no difference. After the latest macOS update, after reboot no display. I had to zap the PRAM before I got a picture. The Mac sees the eGPU, just no image. Beginning to feel like this was wasted money. I wouldn't feel so bad, but it doesn't work with my HP laptop either under Windows 10 Pro.
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Electromen

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  • Real Name: Greg Barringer

Re: No Video 2018 15" MacBook Pro, eGPU and LG 5K Display

PostMon Oct 05, 2020 11:19 pm

What does BM tech support say?
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Stempnakowski

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  • Joined: Thu Sep 17, 2020 7:49 pm
  • Real Name: David Stempnakowski

Re: No Video 2018 15" MacBook Pro, eGPU and LG 5K Display

PostWed Oct 07, 2020 9:27 pm

They have not seen this issue before. Tried the few obvious solutions including downloading new drivers, but the issue persisted. They suggested I contact Apple. Which I did. Apple had not seen it before either. Ran through everything short of OS re-install. Since that is a big pain, I'm waiting for Mac OS 11 final release then I will do a clean install.

Right now, I'm running the MBP with the LG 5K Ultrafine directly connected via Thunderbolt, then an LG 4K UHD connected to the eGPU via thunderbolt to DisplayPort cable. In this configuration, the MBP has no issues and reboots fine with video displaying correctly on both monitors. The BM eGPU doesn't seem to like being connected to the LG 5K display.

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