Macbook 2012 no entry symbol after TM backup on SSD

[nhouse1]

hi everyone. i need some help
i have recently bought a used mid 2012 macbook pro 2.9ghz i7 which is supposed to be quite good for what i need.
i removed the hhd straight away and i placed my old macbook 2008 SSD instead (i simply took it out and replaced it)
after booting, some applications were not working and the macbook was slow. the video was slow and weirdly stuttering so i thought to erase the ssd and transfer the time machine over it.
the fact is that now i can't complete the TM backup and the NO ENTRY symbol appears!
the SSD is curecntly OS journaled formatted and the hhd (that was inside the MB 2012) that i replaced was APFS formatted !
any idea?
is it becasue of the is formatted OS journaled ? cheers and thanks for helping out

 

[Fishrrman]

I'll bet you have an internal drive ribbon cable that is "getting marginal".
This is a well-know "point of failure" on the 2012 non-retina MBP's.

An SSD can make this evident because an SSD seems to "need more" from the connecting cable than a flaky cable delivers. That is to say, the cable may "get by" with a platter based hard drive, but its weakness will become evident by swapping that out for an SSD.

Fortunately, it's an easy and cheap fix.
Since you already know how to change the drive, just "go back in" and change out the ribbon cable.
You can get the part number at ifixit.com.
Then, either buy the cable from them, or elsewhere online.

I'll reckon that if you change the cable, you'll be very happy with the results...