Since updating to macOS Sierra, my Seagate 1TB Harddrive isn't being read or mounted by my Retina MacBook Pro (2014) ... It appears in Disk Utility but not in Finder or on the Desktop ... In Disk Utility I cannot do anything but format it which I DO NOT want to do .. Any suggestions or help?!
I realised that the disk format is changing from NTFS to EXFAT. I had to use different operating system to read the data and format back to NTFS which I believe Mac OS supports.
I had a similar issue. MacBook Pro running MacOS Ventura with a 4gb WesternDigital External Drive. Hard drive would not mount but would show up in Disk Utility. I purchased the latest version of Disk Warrior and ran this. The drive mounted with Disk Warrior running and I was able to pull off my files.
try using a Windows computer. It will very likely to be mounted and read.
That's funny but it works. I guess something in MacOS messed it up.