I own a 13" MacBookPro, mid-2010. I just replaced the HD with a Samsung SSD (870 EVO SATA 2.5") and the RAM memory to 16 GB (2x8GB). Before the replacement I cloned the HD to the Samsung SSD. After I finished downloading Mac OS High Sierra, every time I start my computer all I get is a grey screen with a "do not enter coin" (circle with a diagonal hash stripe).
How do I proceed from here?
A 2010 Mac can only run up to macOS 10.13 High Sierra.
If you have trouble running the macOS 10.13 High Sierra installer from within macOS you can try running the installer from Safe Mode, or use Recovery Mode (Command + R), Internet Recovery Mode (Command + Option + R), or a bootable macOS 10.13 USB installer instead.
FYI, Disk Utility is not good at cloning a macOS boot drive (in fact Disk Utility isn't good at much at all). If you want to clone a drive reliably, then you should consider using Carbon Copy Cloner (CCC). I've never had any issues using CCC to clone a macOS boot drive since CCC also recreates the hidden recovery partition.
A 2010 Mac can only run up to macOS 10.13 High Sierra.
If you have trouble running the macOS 10.13 High Sierra installer from within macOS you can try running the installer from Safe Mode, or use Recovery Mode (Command + R), Internet Recovery Mode (Command + Option + R), or a bootable macOS 10.13 USB installer instead.
FYI, Disk Utility is not good at cloning a macOS boot drive (in fact Disk Utility isn't good at much at all). If you want to clone a drive reliably, then you should consider using Carbon Copy Cloner (CCC). I've never had any issues using CCC to clone a macOS boot drive since CCC also recreates the hidden recovery partition.
The circle with line through it means the system detected a bootable macOS install, but for some reason that OS is not compatible with the Mac or the OS is damaged/corrupt. There is a good chance your old hard drive was failing and corrupted a portion of the OS or you have an issue with the new RAM. What make & model is the new RAM? Macs are very picky about the memory they use so it is best to only use memory from either Crucial or OWC.
I connected the Samsung SSD to the MacBookPro USB port using SATA to USB adapter and using Disk Utility cloned the Mac HDD.
I don't remember . Maybe 10.14 or 15?
Yes, the macOS booted fine after cloning.
I was about to try your suggestions but I felt intimidated so I brought my MacBookPro to a computer professional for help. When he asked me what the problem is, I explained everything and turned on my MacBook. To our surprise, after I put in the password for the new SSD, it just turned on and all my documents, music , pictures were there and able to connect to internet which is what I am using now. Long story short everything is working just fine and fast. Like new. Did it just need a few days to get settled in?
How did you clone the drive?
What OS was on the original hard drive?
Did macOS boot fine from the new Samsung SSD after the clone?
Upgrading HD to SSD and Memory RAM
