martin_weiss Posted October 7, 2015 Share Posted October 7, 2015 I am having a strange issue which I didn't have in Yosemite. When I boot my machine, sometimes my monitor won't turn on, it's like there's no signal from the DisplayPort. If I press the restart button, it works fine. I've encountered this most on cold starts (i.e., not when rebooting). Also, it doesn't happen every time I turn on the computer. Any help would be greatly appreciated! Link to comment https://www.insanelymac.com/forum/topic/308504-black-screen-on-boot-only-sometimes/ Share on other sites More sharing options...
spakk Posted October 7, 2015 Share Posted October 7, 2015 after the restart a crash report should be issued. What information can you read from the report? Edit: otherwise upload the reports and write on when the error occurred, with an approximate time.... perhaps someone can evaluate the report. Link to comment https://www.insanelymac.com/forum/topic/308504-black-screen-on-boot-only-sometimes/#findComment-2174493 Share on other sites More sharing options...
martin_weiss Posted October 8, 2015 Author Share Posted October 8, 2015 Thanks for your reply. There is no crash report issued (I'm not prompted when I log in). Is there anywhere I can read about what goes wrong during startup (can I find it using Console?)? It's difficult otherwise, because it only happens some times, and the screen doesn't turn on, so verbose mode is useless... Link to comment https://www.insanelymac.com/forum/topic/308504-black-screen-on-boot-only-sometimes/#findComment-2174917 Share on other sites More sharing options...
spakk Posted October 8, 2015 Share Posted October 8, 2015 go to root /var/ then open a new tab with the right mouse-click, then go to folder /var/log/ and open the system.log with the console.app or with Smultron.app. Maybe you'll find there an indication of the problem. Link to comment https://www.insanelymac.com/forum/topic/308504-black-screen-on-boot-only-sometimes/#findComment-2174933 Share on other sites More sharing options...
martin_weiss Posted October 13, 2015 Author Share Posted October 13, 2015 I've looked in system.log, but I'm not sure what to look for The log is quite long. I'm really not sure what to do about this. It's quite annoying. Only thing I know is that it started when I upgraded to El Capitan. If only the screen turned on I could use the -v boot flag, so I could see what's going on, but it doesn't.... Link to comment https://www.insanelymac.com/forum/topic/308504-black-screen-on-boot-only-sometimes/#findComment-2177222 Share on other sites More sharing options...
CooSee Posted October 13, 2015 Share Posted October 13, 2015 I am having a strange issue which I didn't have in Yosemite. When I boot my machine, sometimes my monitor won't turn on, it's like there's no signal from the DisplayPort. If I press the restart button, it works fine. I've encountered this most on cold starts (i.e., not when rebooting). Also, it doesn't happen every time I turn on the computer. Any help would be greatly appreciated! +1 (sometimes on cold starts) the culprit is not your System. i don't know much about Clover - maybe there's a possibility to debug. ElCap is unusable for me atm, so i switched back to Yosemite good luck. Link to comment https://www.insanelymac.com/forum/topic/308504-black-screen-on-boot-only-sometimes/#findComment-2177228 Share on other sites More sharing options...
martin_weiss Posted October 13, 2015 Author Share Posted October 13, 2015 Hmm. Not nice. I was hoping I had made an obvious mistake somewhere which was causing this... Hopefully this will be resolved at some point. If anyone else has the same problem and finds a solution, please post it here. EDIT: Just updated my BIOS to F5. We'll see if the problem persists. Link to comment https://www.insanelymac.com/forum/topic/308504-black-screen-on-boot-only-sometimes/#findComment-2177356 Share on other sites More sharing options...
martin_weiss Posted October 15, 2015 Author Share Posted October 15, 2015 Updating the BIOS to the latest version didn't solve the problem (for me at least). Link to comment https://www.insanelymac.com/forum/topic/308504-black-screen-on-boot-only-sometimes/#findComment-2177887 Share on other sites More sharing options...
martin_weiss Posted October 19, 2015 Author Share Posted October 19, 2015 I think I located the problem. Actually it might be related to what Anachronaut is talking about in his thread about Clover boot entries. I used to have a couple of data disks attached beside the SSD which I'm running my system off of. One of these disks previously had Clover on them (might actually stil have, but I thought I emptied the EFI partition). I haven't had any problems since I pulled all disks except my system disk... Link to comment https://www.insanelymac.com/forum/topic/308504-black-screen-on-boot-only-sometimes/#findComment-2179473 Share on other sites More sharing options...
Ritte Posted October 19, 2015 Share Posted October 19, 2015 I had the same problem: http://www.insanelymac.com/forum/topic/308788-black-login-screen/ As I figured out, the computer does boot into the system. But the graphics is not working when entering the "log in"-screen, but I could connect to it with screen sharing. The solution for my was to turn on "automatic login" in OS X, that way I booted straight into the system. Link to comment https://www.insanelymac.com/forum/topic/308504-black-screen-on-boot-only-sometimes/#findComment-2179664 Share on other sites More sharing options...
martin_weiss Posted October 19, 2015 Author Share Posted October 19, 2015 Today I had the same problem, so I haven't figured out the problem it turns out... Thanks for your comment, Ritte. I'll try that out. By the way, how did you figure out that the computer boots into OS X? If true, this might be a bug that could be solved in a future update, no? Link to comment https://www.insanelymac.com/forum/topic/308504-black-screen-on-boot-only-sometimes/#findComment-2179669 Share on other sites More sharing options...
AudiSport Posted October 19, 2015 Share Posted October 19, 2015 I have also seen this a couple times. The first time I rebooted by the power button and it came up correctly. The second time I just left it and after about 5 or so minutes the login screen appeared. Link to comment https://www.insanelymac.com/forum/topic/308504-black-screen-on-boot-only-sometimes/#findComment-2179692 Share on other sites More sharing options...
Ritte Posted October 19, 2015 Share Posted October 19, 2015 Today I had the same problem, so I haven't figured out the problem it turns out... Thanks for your comment, Ritte. I'll try that out. By the way, how did you figure out that the computer boots into OS X? If true, this might be a bug that could be solved in a future update, no? I noticed that afp and screens sharing was available from my other computer, so I tried screen sharing and logged in. Once logged the display turns on. When booting in safe mode,I can reach log in screen. Link to comment https://www.insanelymac.com/forum/topic/308504-black-screen-on-boot-only-sometimes/#findComment-2179747 Share on other sites More sharing options...
martin_weiss Posted October 28, 2015 Author Share Posted October 28, 2015 I haven't had this problem after updating to 10.11.1. Can anyone else confirm? Link to comment https://www.insanelymac.com/forum/topic/308504-black-screen-on-boot-only-sometimes/#findComment-2183015 Share on other sites More sharing options...
AudiSport Posted October 28, 2015 Share Posted October 28, 2015 I have experienced it on 10.11.1. Link to comment https://www.insanelymac.com/forum/topic/308504-black-screen-on-boot-only-sometimes/#findComment-2183074 Share on other sites More sharing options...
martin_weiss Posted November 5, 2015 Author Share Posted November 5, 2015 I still haven't had this problem since updating to 10.11.1. Crossing my fingers. Link to comment https://www.insanelymac.com/forum/topic/308504-black-screen-on-boot-only-sometimes/#findComment-2185631 Share on other sites More sharing options...
AudiSport Posted December 21, 2015 Share Posted December 21, 2015 I am still seeing this randomly on 10.11.2. Setting auto login doesn't fix it for me. But so far if I just leave it alone for 5 to 10 minutes the login screen (or desktop if auto login is on) will appear. One thing I have noticed is that it seems to hang on the second stage boot logo as it never appears and after waiting the 5 to 10 mins the second stage progress bar shows for a couple of seconds and then I see the login screen. Link to comment https://www.insanelymac.com/forum/topic/308504-black-screen-on-boot-only-sometimes/#findComment-2199411 Share on other sites More sharing options...
=)(= Posted December 24, 2015 Share Posted December 24, 2015 What GPU? I experience the same thing occasionally. Monitor loses signal at the login screen, but once I re-plug the mDP cable, the signal comes back on. I can see the text in verbose mode. Link to comment https://www.insanelymac.com/forum/topic/308504-black-screen-on-boot-only-sometimes/#findComment-2200070 Share on other sites More sharing options...
AudiSport Posted December 25, 2015 Share Posted December 25, 2015 My GPU is a NVidia 9500GT connected to 2 displays both via DVI. Link to comment https://www.insanelymac.com/forum/topic/308504-black-screen-on-boot-only-sometimes/#findComment-2200314 Share on other sites More sharing options...
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