I have a G7 7588 laptop with a M.2 SSD and an empty 2.5" bay.  I was planning to upgrade the M.2 SSD so was going to install a Samsung 850 PRO SSD in the HDD bay.  Initially when I installed it, the system immediately recognized it, I was able to initialize and format it and even use the Samsung data migration utility to copy the disc image to the 850 PRO.  The laptop booted from it and all was good.  This was just a test to make sure that the utility would transfer data, and while it did -- it didn't transfer the dedicated partitions, so I decided to use another method.

Anyway, since the laptop was booted to the 850 PRO, I shut it down to remove the 850 and rebooted to the M.2 SSD.  I then connected the 850 to a USB adapter so I could reformat it and remove the service partition that had been created.  After that, the laptop would not detect the drive in the 2.5" bay any more.  USB adapter works fine -- just not in the internal bay.  I suspected that the ultra fragile SATA cable might have become damaged when I unplugged the drive, so I contacted Dell Support, but they were of absolutely no use since they claim that the 850 PRO is a 3rd party device that needs special drivers and firmware to make it work (yes -- they actually wrote that).  I know that's not the case because it worked initially (and actually had better performance than the M.2 SSD that it came with). 

Incidentally, the 850 PRO is not even shown in BIOS when installed in the internal bay.

Has anybody else had a similar issue?  Is the SATA cable really that fragile?  Any advice?

 

TL;DR: G7 stopped detecting internal 2.5" SSD - suspect bad SATA cable.