Before upgrading to High Sierra or Mojave, as a maintenance measure, please make sure that you restart your computer BEFORE beginning the install. This ensures that any runaway background processes have ceased, allowing for a smoother upgrade.
Make sure that the software and services you use will function with the newest upgrades. You can check here for any MIT related compatibility issues. Once you upgrade, it may be difficult to revert to an earlier version.
As always, prior to any operating system change it is suggested by IS&T that users have a full backup of their computer. CrashPlan is the recommended backup solution for desktops and laptops. CrashPlan is cloud-based and is offered at no cost to members of the MIT community.
Apples most recent Operating Systems, High Sierra (10.13) and Mojave (10.14), utilize a new file system known as APFS (Apple File System) instead of the HFS+.
APFS changes the manner in which the computer accesses files. While this does increase the speed at which files are read and manipulated, this also makes the computer more prone to problems when the system files are being adjusted during OS upgrades.
Periodically restarting your computer will help avoid such problems.