And how you plan to use your SanDisk SSD Portable drive. Read on and choose which is the best for you. Time Machine will only backup to a certain Mac format. What format you pick depends on what you’re planning to use your SanDisk Portable SSD drive for. What's Best On A SanDisk Portable SSD For A Clone Drive.Using Your SanDisk Extreme Portable On A Mac As A Boot Drive.Best Format For A Time Machine Backup On Your SanDisk Extreme Portable.Best For Using SanDisk Extreme Portable Between Your Mac And Windows PC.Plugging In Your SanDisk Portable SSD To Newer And Older Macs and MacBooks.Are You Only Using Your SSD SanDisk Portable On Newer Macs?.What About Sticking With The Extreme SSD Portable Out Of The Box Format?.