Apple Diagnostics does not function anymore

Mac startup key combinations

About Mac startup tones

Be sure to check your keyboard's connection to the computer. You need to pair it via BT for it to work correctly.

A Troubleshooting Procedure that may Fix Problems with macOS El Capitan or Later

You should try each, one at a time, then test to see if the problem is fixed before going on to the next.

Be sure to backup your files before proceeding if possible.

1. Shutdown the computer, wait 30 seconds, restart the computer.
2. Disconnect all third-party peripherals.
3. Resetting your Mac’s PRAM and NVRAM
4. Reset the System Management Controller (SMC)
5. Reset your Startup Disk and Sound preferences.
6. Start the computer in Safe Mode. Test in safe mode to see if the problem persists, then restart normally. Also, see Use safe mode to isolate issues with your Mac - Apple Support and Playing Safe- what does Safe mode do?.
7. Use Apple Hardware Test to see if there is any hardware malfunction. How to invoke and interpret the Apple hardware tests - CNET.
8. Repair the disk by booting from the Recovery HD. Immediately after the chime hold down the Command and R keys until the Utility Menu appears. Choose Disk Utility and click on the Continue button. Select the indented (usually, Macintosh HD) volume entry from the side list. Click on the First Aid button in the toolbar. Wait for the Done button to appear. Quit Disk Utility and return to the Utility Menu. Restart the computer from the Apple Menu.
9. Repair permissions on the Home folder: Resolve issues caused by changing the permissions of items in your home folder.
10. Create a New User Account Open Users & Groups preferences. Click on the lock icon and enter your Admin password when prompted. On the left under Current User click on the Add [+] button under Login Options. Setup a new Admin user account. Upon completion log out of your current account then log into the new account. If your problems cease, then consider switching to the new account and transferring your files to it - Transferring files from one User Account to another.
11. Download and install the OS X El Capitan 10.11.6 Combo Update or 10.12.6 Combo Update or Download macOS High Sierra 10.13.6 Combo Update as needed.
12. Reinstall OS X by booting from the Recovery HD using the Command and R keys. When the Utility Menu appears select Reinstall OS X then click on the Continue button.
13. Erase and Install OS X Restart the computer. Immediately after the chime hold down the Command and R keys until the Apple logo appears. When the Utility Menu appears:

1. Select Disk Utility from the Utility Menu and click on Continue button.
2. When Disk Utility loads select the drive (out-dented entry) from the Device list.
3. Click on the Erase icon in Disk Utility's toolbar. A panel will drop down.
4. Set the Format type to APFS (for SSDs only) or Mac OS Extended (Journaled.)
5. Click on the Apply button, then wait for the Done button to activate and click on it.
6. Quit Disk Utility and return to the Utility Menu.
7. Select Reinstall OS X and click on the Continue button.

14. If none of the above helps then see How to Downgrade macOS High Sierra and macOS Reversion- How to Downgrade from High Sierra.

15. If you get here without success then make an appointment at the Apple Genius Bar for service. If you need to find an Apple Store - Find a Store - Apple.

klausfromlimburgerhof wrote:

I do not get anymore "Apple Diagnostics" by pressing "D" on keyboard during startup.

I have run "Apple Diagnostics" last on 5 th of may this year with macOS 10.13.5.

Now i have updated to 10.13.6. Could it be that this is the point ?

If holding down the D key at startup doesn't start Apple Diagnostics:

If you're using a firmware password, turn it off. You can turn it on again after using Apple Diagnostics.

Hold down Option-D at startup to attempt to start Apple Diagnostics over the Internet.

How to use Apple Diagnostics on your Mac - Apple Support

Future updates will not solve your specific problems nor any other problems except those that were reported already. You might try using a different keyboard to determine if yours has failed. It has nothing to do with High Sierra. You might have an installation that is malfunctioning but you aren't willing to replace it in order to find out.

klausfromlimburgerhof wrote:

but i have checked before if there is a firmware password set : it is not.

Also the key combination "option+d" does not work, same as with "D" alone.

Independent of the Diagnostic, are you having some other technical issue with your 2017 iMac Pro ?

klausfromlimburgerhof wrote:

no i have not any issues with my iMac Pro. Everything works fine and flawlessly. It is a superbe machine my iMac Pro.

But I am in the habit of testing the hardware from time to time, particuluarly the fans.

Do you think, my problem would be solved with Mojave when it is coming up in September ?

Good to hear klausfromlimburgerhof.

I can not speculate on the macOS 10.14 Mojave, however I would not rule it out for regaining your Diagnostic.