I have the newest version of iMac and I want to make an time machine backup on my external USB 3.0 hard drive. But the transfer rate is very very slow. The system shows an backup-time of about 100 days (!!!!!) to save 450 GB. What's going on? The hard drive is also really new and works normally if I use it as a normal hard drive (also with other Macs)... Who can help mejQuery19109327568920768398_1427522413820??

I have the newest version of iMac and I want to make an time machine backup on my external USB 3.0 hard drive. But the transfer rate is very very slow. The system shows an backup-time of about 100 days (!!!!!) to save 450 GB. What's going on? The hard drive is also really new and works normally if I use it as a normal hard drive (also with other Macs)... Who can help mejQuery19109327568920768398_1427522413820??