I upgraded my iMac to Mojave and now when connecting my MacBook to my iMac as an external monitor the display image is blank or unusable. I am using the lightning cable and pressing Command + F2 to connect the screens. All I get is a blank screen on the iMac.
iMac 27", macOS 10.14
magmo43 wrote:
I upgraded my iMac to Mojave and now when connecting my MacBook to my iMac as an external monitor the display image is blank or unusable. I am using the lightning cable and pressing Command + F2 to connect the screens. All I get is a blank screen on the iMac.
Are you sayinhg your configuration worked successfully before— and now your Upgrade to 10.14.4 it does not?
what exact "Macbook" /model /year /size /retina /touchbar is this ?
What exact lightening cable?
Is this the charging cable that came with Macbook?
Identify the ports on your Mac - Apple Support https://support.apple.com/en-us/HT201736
Get help with video issues on external displays connected to your Mac - Apple Support https://support.apple.com/en-us/HT201177
magmo43 wrote:
I upgraded my iMac to Mojave and now when connecting my MacBook to my iMac as an external monitor the display image is blank or unusable. I am using the lightning cable and pressing Command + F2 to connect the screens. All I get is a blank screen on the iMac.
Are you sayinhg your configuration worked successfully before— and now your Upgrade to 10.14.4 it does not?
what exact "Macbook" /model /year /size /retina /touchbar is this ?
What exact lightening cable?
Is this the charging cable that came with Macbook?
Identify the ports on your Mac - Apple Support https://support.apple.com/en-us/HT201736
Get help with video issues on external displays connected to your Mac - Apple Support https://support.apple.com/en-us/HT201177
magmo43 wrote:
UPDATE: I got it to work again but the iMac screen is very dark to the point where you see almost a screen burn type display of the MacBook's screen. Its not usable and cannot see where my cursor is located. It seems like it would be a brightness issue but my brightness is all the way up.
I would try a different cable to test.
Try resetting the SMC https://support.apple.com/en-us/HT201295
Yes the configuration worked before I upgraded to Mojave. My setup is:
iMac (27-inch, Late 2013, Mojave 10.14.4) and a MacBook Pro (15-inch, Late 2018, Mojave 10.14.4)
Using the Apple Thunderbolt Cable (2.0 m)and the Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter to connect both machines.
No this is no the charging cable.
The ports on the iMac are Thunderbolt ports (I have 2 ports) and the ports on the Mac Book are Thunderbolt 3 (USB-C)
I got it to work once upon restarting the iMac but since then it displays a blank screen. I have viewed the link you sent and tried all options which didn't solve my issue. Thanks for the help.
UPDATE: I got it to work again but the iMac screen is very dark to the point where you see almost a screen burn type display of the MacBook's screen. Its not usable and cannot see where my cursor is located. It seems like it would be a brightness issue but my brightness is all the way up.
External display not connecting
