slicksleeve wrote:
I can't get my late 2009 15" MacBook Pro to boot correctly. It will occasionally boot but mainly gets hung up during boot up while the apple is displayed in the background. During startup the circle with a slash appears then eventually get to the apple logo and progress bar. I've tried to boot with the startup disk which occasionally works. I installed a new hard drive along with the El Captian OS X (this problem existed before I installed the new drive). I was able to get it to boot correctly a few times but it mainly fails to boot up. What are some other things I can try? I read somewhere that disconnecting the battery to do a power reset will help. I'm about to give on on trying to repair this.
I would not recommend disconnecting the battery— this was applicable to removable batteries—ie the white/black plastic Macs that had a battery access panel that dropped out from the bottom.
Try resetting NVRAM/PRAM http://support.apple.com/kb/ht1379
(allow for at least 3 series of the tones to complete before letting go the key combination.)
Try resetting the SMC https://support.apple.com/en-us/HT201295
If your Mac doesn't turn on or start up – Apple Support
Does this Mac allow for Recovery?
Boot into Recovery (Command R) and from the dropdown menu: Utilities> Disk Utility> run the First Aid on your Macintosh HD (and the "Macintosh HD-Data" volume as well if Catalina) If errors are found and repaired, run again until no errors reported.
Recovery: https://support.apple.com/en-us/HT204904
Can you boot to an external source? Holding the Option key will recognize:
— a boot clone,
— a USBinstaller,
—and Time Machine which is bootable as well.
