mac pro late 2013 freezes with spinning wheel

I assume thats 0*0. not the letter x?

I gonna try it. If this works then there really is a very deep problem brewing within apple. If 1 line of setting can stop random crashes and which was detected long ago, this will not inspire confidence for apple's pitch on quality and ease of use. I gonna start ranting again because I lost so much productivity time and had so much grief for the 1st macpro I bought with hard earned money

no, the command is exactly

sudo nvram boot-args="dart=0x0"

with "x" letter

that 0x0 is programmer's shorthand. the leading zero-x says the next item should be interpreted as "Hex" (short for hexadecimal [base-16]), and the last zero is the base-16 value, zero. 0x0 for hexadecimal zero.

You can also cut-and-paste a line someone says is "exactly this".

Hi Max,

do you think my problem is caused by the same bug?

Thanks! Ciao ciao

If when Mac freezing, you disconnect Thunderbolt Cable, and reconnect after some seconds, and de-freeze but work slowly, the problem is the same that have me too.

BUT, I think that I have solved with the workaround that I wrote in thread.

Let me know

Max

Any news (you or other users) about usage after workaround?

Max

this is the longest I've been without a gpu crash. This seems to be looking good. If the fix is only 1 line of setting, the is going to be very embarrassing on apple's part. I hope i didnt jinx it by writing about it

I've had the nvram setting applied for most of the weekend and I'm still seeing the freezing/lockups. I can still bring it back to life by removing the thunderbolt cable and connecting it to a different port but this is totally unacceptable. I guess I'll be dragging my Mac Pro and 27" Thunderbolt display downtown to an Apple store that's packed with holiday shoppers just so some 'genius' can tell me they can't reproduce the problem again. Sigh.

At this point I'm thinking it might just be easier to sell this computer and buy something that doesn't have this problem.

Hello.

Be careful that the parameter is setted, with

nvram -p | grep boot-args

the result must be : dart=0x0

in my case, the first time the system doesn't set correctly the parameter.

I Had to do this thing two times.

let me know

Max

Just tried setting nvram again for good measure. Will report back.

Check the appliance of parameter with

nvram -p | grep boot-args

Max

I confirm that the workaround seems to solve the problem of slowness of the thunderbolt.

Unfortunately it does not solve the problem of disconnection bluetooth and audio loss 😟

I correct: I have the same problems! With my $ 4K MAC PRO is impossible to work!

ps. The Apple service has just replaced the logic board with connections thunderbolt, bluetooth, usb, etc. Same problems

The suggested fix did not work for my Mac Pro (late 2013) with a single 4K monitor connected via display port and using Mac OS 10.11.2. My current issue is that if I set the Energy Saver control panel to turn the display off after say 5 minutes and after my monitor goes into a power saving mode, I cannot get monitor to reactivate. Disconnecting the Display port connection and reconnecting does not make a difference. I think my Mac Pro is probably still alive, but the monitor will not reactivate, so I've been manually powering down and rebooting. My current "fix" is to disable the option to turn off monitor ("Never" setting), then manually turn off power to my monitor whenever I want to blank it out. Turning on the monitor power later will restore monitor display. I also do not allow Mac to go to sleep.

Just to give some history with my Mac Pro, when trying to install Mac OS 10.11.1 I had major lockup problems while the display was active. My screen would slowly start showing some jerkiness, then eventually lock up with spinning ball. Manual power down and reboot sometimes brought back my system, but sometimes would lock up during startup, so I decided to revert back to a Mac OS 10.10.5 and wait for the next update (10.11.2). When Mac OS 10.11.2 came out recently, I did the update and the original lockup problems did not reoccur, except for the problem I identified in first paragraph.

I had no problems at all with my 4K system using Mac 10.10.5. I was also able to update to 10.11.0 with no problems. All my problems started with Mac OS 10.11.1 update. Prior to getting my 4K monitor, I was using the Apple 30' Cinema display with an adaptor to Thunderbolt connection. I had no problems with that either on my Mac Pro using Mac OS 10.10.5.

Hopefully the suggested fix will help others, but it did not help me.

Paul