Macbook pro A1278 wont boot (stuck on apple loading screen) without smc reset ?

[alors]

My macbook turns on but will be stuck on loading screen if boot internally, after smc reset it boots fine into os but if restarted or shut down, wont boot (stuck on loading screen) without smc or nvram reset, once reset the smc or sometime nvram it boots fine into os. it boot perfectly fine if hard drive connected externally through usb without any problems. “problem is definitely not related to hard drive or macos” hard drive been replaced twice, hdd flex cable also been replaced, os been reinstalled freshly many times. i know its an old machine not worth wasting time or money but i might want to do it as a fun project so any help or suggestions what could be the possible component behind it ? it has been previously repair few years ago for no power (was completely dead) not sure what component has been replace.
Macbook pro Mid 2009, A1278

 

[Randy B. Singer]

While booted in Safe Mode, go into System Preferences --> Users & Groups (or Accounts) --> Login Items
and disable all login items by highlighting them one at a time and clicking on the little box with the negative sign in it. Restart normally and see if things are all better.

See:

https://support.apple.com/guide/mac-help/if-your-mac-doesnt-start-up-as-expected-mchlp2889/mac

https://support.apple.com/guide/mac-help/if-your-mac-stops-or-delays-while-starting-up-mchlp2580/mac

 

[alors]

While booted in Safe Mode, go into System Preferences --> Users & Groups (or Accounts) --> Login Items
and disable all login items by highlighting them one at a time and clicking on the little box with the negative sign in it. Restart normally and see if things are all better.

See:

If your Mac doesn’t start up as expected

If your Mac stops or delays while starting up

hi, thanks for your reply. i just checked my login items in safe mode but the list is empty. in this macbook i have replaced the hard drive twice with that i freshly installed the macos but the problem persists but its not constant. its more like sometimes it happens and sometimes it doesn't. sometimes in sleep mode it cant be back on and restart by itself showing me a kernel panic. sometimes i turn it on and it boots just fine. sometimes a bit slow and sometimes it just stuck there forever and then i have to try to reset smc and pram and somehow get it work.