"Problems were found with the partition map which might prevent booting"

Hi,

The only way to change the partition map is be formatting the HD, meaning everything will be erased. If you have your data backed up, erase your HD via Recovery Mode or Internet Recovery Mode, install the OS, and restore the data from your backup: https://support.apple.com/en-us/HT201314

Please start a new thread with your issue specified.

It sounds like either a bad cable or the SSD itself.

What if I don't have my files backed up? How can I get them backed up? Nothing shows up in time machine

Hi, I found this thread as I have a similar problem which started only after I updated my Sierra version to the newest. After 2 days of effort I finally was able to reinstall Sierra but with little or no computer functionality. I can open someapplications but can't load any internet pages or the App Store despite good connection to the internet which has not failed me in 2 days of trying to troubleshoot this disaster.

Tried making a boot disk from Terminal but it did not work.

I did reformat my internal hard drive (SSD) but it is still showing the same error message in Disk Utility: "Problems were found with the partition map which might prevent booting."

I tried reinstalling Sierra again from recovery mode but was denied permission and/or told it was a bad command. I have tried to reinstall it perhaps 20 times today with only the one semi-successful effort.

I wonder if it might be a data cable problem as I had to replace it a few months ago. The HD is 7 months old.

I take it you are running Sierra when you got the problem. These types of happening is why I have Yosemite bootable at any time to get to its Disk Utility.

If you are running sierra, try reinstalling it from app store in safe mode! it fixed my exact same error! hope this helps

I wish I had never upgraded to the latest Sierra version. Was working fine with 10.12.1. Now I am stuck with a reformatted hard drive and still no usable computer.