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Hi, i am not able to update my macbook pro from macOS Sierra version 10.12.6 to macOS catalina.
- Thread starter pratik g
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Yes well, deleting the boot drive is typically undesirable when the machine is running 
The error message explains what has to happen. I am at a loss as to why it would not be GUID partitioned... something strange must have happened to get it into this non-default state.
if you would select the SAMSUNG SSD item in the list and screenshot/post that info, we could confirm the problem.
Basically, you need to wipe the drive and re-partition it the way the OS requires. This can be done from internet recovery, if that is available to you. In your case, a DVD installer can work too. You need to run Disk Utility from recovery/DVD/usb boot disk and then partition the drive from the there
The error message explains what has to happen. I am at a loss as to why it would not be GUID partitioned... something strange must have happened to get it into this non-default state.
if you would select the SAMSUNG SSD item in the list and screenshot/post that info, we could confirm the problem.
Basically, you need to wipe the drive and re-partition it the way the OS requires. This can be done from internet recovery, if that is available to you. In your case, a DVD installer can work too. You need to run Disk Utility from recovery/DVD/usb boot disk and then partition the drive from the there
I wouldn't upgrade to Catalina.
I'd take that 2012 MacBook to Mojave and "leave it there".
For many folks, Catalina remains "a bag of hurt" at this time. Mojave (on the other hand) is quite smooth and stable.
You will still have to reformat the drive to get to Mojave.
I'll offer a suggestion on how to do this, in a way that will PRESERVE YOUR DATA if something goes wrong:
First, you need a copy of the Mojave installer. This link should hook you up to the App Store for downloading:
It will download into your Applications folder, but don't run it yet.
Next...
1. Get an external drive
2. Download CarbonCopyCloner from here:
CCC is FREE to download and use for 30 days, this costs you nothing.
3. Use CCC to create a cloned backup of your internal drive to the external drive
4. Now you are BACKED UP and can reformat the internal drive.
Now...
a. BOOT FROM the external drive -- restart, and IMMEDIATELY hold down the option key until the startup manager appears. Select the external drive using the pointer and hit return.
b. You should boot from the external drive. It will look EXACTLY like the internal drive (after all, it's a "clone")
c. Open Disk Utility. Go to the "View" menu and choose "show all devices".
d. Now, in the device list on the left, select the topmost item that represents your physical internal drive (the SSD).
e. Click the erase button and choose APFS, GUID partition format.
f. Erasing should take only a few seconds, then quit Disk Utility.
Now...
a. Open the Mojave installer (in your applications folder)
b. Begin "clicking through", BUT...
c. ...when asked WHERE you want to install, choose the INTERNAL DRIVE (remember that you're booted from the external).
d. Let the install proceed. It will take one or more restarts, and will take some time. BE PATIENT.
e. When done, you should see the setup screen ("choose your language")
Then...
1. Begin setup.
2. At the appropriate moment, setup assistant will ask if you wish to migrate from another Mac or drive. YES, you want to do this, so....
3. ..."aim" setup assistant at the EXTERNAL drive (your backup)
4. It will take a little time for setup assistant to "digest" everything. BE PATIENT -- you don't get much feedback while this is happening.
5. I recommend that you accept all the defaults
6. Then, turn setup assistant loose and again be patient, it will take some time.
When done, you should see "your old login screen", so...
... login and "look around".
BE AWARE that some older programs may not run or may need upgrades.
Good luck!
I'd take that 2012 MacBook to Mojave and "leave it there".
For many folks, Catalina remains "a bag of hurt" at this time. Mojave (on the other hand) is quite smooth and stable.
You will still have to reformat the drive to get to Mojave.
I'll offer a suggestion on how to do this, in a way that will PRESERVE YOUR DATA if something goes wrong:
First, you need a copy of the Mojave installer. This link should hook you up to the App Store for downloading:
It will download into your Applications folder, but don't run it yet.
Next...
1. Get an external drive
2. Download CarbonCopyCloner from here:
CCC is FREE to download and use for 30 days, this costs you nothing.
3. Use CCC to create a cloned backup of your internal drive to the external drive
4. Now you are BACKED UP and can reformat the internal drive.
Now...
a. BOOT FROM the external drive -- restart, and IMMEDIATELY hold down the option key until the startup manager appears. Select the external drive using the pointer and hit return.
b. You should boot from the external drive. It will look EXACTLY like the internal drive (after all, it's a "clone")
c. Open Disk Utility. Go to the "View" menu and choose "show all devices".
d. Now, in the device list on the left, select the topmost item that represents your physical internal drive (the SSD).
e. Click the erase button and choose APFS, GUID partition format.
f. Erasing should take only a few seconds, then quit Disk Utility.
Now...
a. Open the Mojave installer (in your applications folder)
b. Begin "clicking through", BUT...
c. ...when asked WHERE you want to install, choose the INTERNAL DRIVE (remember that you're booted from the external).
d. Let the install proceed. It will take one or more restarts, and will take some time. BE PATIENT.
e. When done, you should see the setup screen ("choose your language")
Then...
1. Begin setup.
2. At the appropriate moment, setup assistant will ask if you wish to migrate from another Mac or drive. YES, you want to do this, so....
3. ..."aim" setup assistant at the EXTERNAL drive (your backup)
4. It will take a little time for setup assistant to "digest" everything. BE PATIENT -- you don't get much feedback while this is happening.
5. I recommend that you accept all the defaults
6. Then, turn setup assistant loose and again be patient, it will take some time.
When done, you should see "your old login screen", so...
... login and "look around".
BE AWARE that some older programs may not run or may need upgrades.
Good luck!