I use an iMac 21.5 inches [mid-2011]. 2.5 GHz Intel core i5 processor, AMD Radeon HD6750M 572 MB graphics.

I use the above mentioned model iMac. When hold down the D key after the computer starts, Apple Hardware Test icon does not appear on the screen.  Any suggestions why and how fix this problem


Go to > OS X El Capitan: use the Diagnostics of Apple or Apple Hardware Test

and carefully follow the instructions in steps 2. and 3. in the section "use Apple Hardware Test".

2. disconnect all external devices except the keyboard, mouse, screen and speakers. If you have an Ethernet cable or an external DVD drive, disconnect it.

3. choose the Apple menu > restart, and then press and hold D for the Mac is restarted.


Tags: Mac

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