upgrade causes errors

Hi all, I have a 2009 Flashed 5,1 Mac Pro that originally came with the single 2.66ghz CPU. I upgraded to a 2010-2012 dual CPU tray with the quad core CPU’s looking to eventually upgrade to dual X5690’s and 1333ghz RAM in the future. My issue is that after installing the stock dual CPU tray...

Hi. Upgrading a MacBook from Mojave to Big Sur, I get the error message in the subject. Reboot did not help. What can I do to either get back to the previous OS or continue with the installation? Thanks for your help, F.

Hi, on Macbook7,1, using dosdude1 patcher, i upgraded from High Sierra to Catalina.Most of stuff went smooth and mac works quite ok with one big exception. Photos app doesnt work as expected, as photos and videos became not available. Thumbnails are grey and after clicking on them, I can see...

I have a iPhone 6S Plus, ios 12.3.1 that is jailbroken with unc0ver. Everything works fine, except I want to go to ios 13 as some games do not run on ios 12 anymore. I have downloaded the iPhone_5.5_13.4_17E255_Restore.ipsw and tried to install it with reiboot and dr.phone. (Windows 10...

Yesterday I upgraded from 10.10 Yosemite to 10.13 High Sierra. Everything seemed fine ... but when I opened Calendar, every single entry and almost every calendar was gone! I tried restoring from Time Machine, using the backup created just before downloading 10.13. It restored every entry up...