This sounds a little weird but I don’t really have any other explanation. My iMac hard drive was failing on SMART status so I decided to bring it into apple and have them replace my drive. They upgraded it to El Capitan (from Yosemity) while doing so. When I got my computer back I managed to restore from my time machine backup without any major issues (aside from USB 2 being super slow). However ever since I got it restored I haven’t been able to do anything with Time Machine. Setting a new backup to run sits on Preparing indefinitely and if I open time machine I can’t click back to any previous days. Does anyone have any idea what might have done this or how I could potentially fix it?