Slow macbook pro 2102 startup

Are you sure your model can handle 16GBs of RAM? Does the computer pass the POST tests (no beeps?) Have you tried booting in Safe Mode?

Boot Into Safe Mode

1. 1. If your Mac isn’t already shut down, then shut it down and wait at least 30 seconds before rebooting.
   2. Immediately, at or before the chime, press and hold down the SHIFT key. 
   3. Release the key after the Apple logo and progress bar appear.
   4. Safe mode startup is much slower than normal startup, so be patient.
   5. When the Login Screen appears enter your admin password. If you use automatic login, then this means you are in safe mode.

About Using Safe Mode

• • Use safe mode to isolate issues with your Mac - Apple Support
  • Playing Safe- what does Safe mode do?

Have you tried booting from the Recovery HD?

donnie218 wrote:

Slow macbook pro 2102 startup

I upgraded my RAM from 8g to 16g now my startup gets stuck half way

What is this 2012 (?)

Verify the RAM is the exact spec for your machine. Best to buy high quality RAM from trust dealer, like

Best in matched pairs and to buy RAM from reliable source with the exact specs.


Usually a lifetime guarantee on RAM from third party source like:

https://eshop.macsales.com/shop/apple/memory/

http://www.crucial.com/usa/en

Try re-seating the RAM: MacBook Pro: How to remove or install memory -

Apple Support https://support.apple.com/en-us/HT201165


you are testing for both bad RAM or bad bank—

one stick at a time in each bank, If the RAM sticks prove to work individual—and banks work individually.

Other known issues are: 

worn clips

or RAM banks slightly distorted/out of flat (use shims)