Can I return to Sierra by way of a time machine backup
I have done an update on my Macbook air to High Sierra from Sierra and now get poor performance which at times is very frustrating. Can I use a back up on Time Machine to get back to Sierra or would OS still be High Sierra
iMac (21.5-inch Mid 2010), OS X Mavericks (10.9.5), 3.2 GHz Intel Core i3, 4GB memory,
