SOLVED: MacBook Will Not Start Up After macOS Update Here are some details -bash-3.2# diskutil listĢ: Apple_CoreStorage Macintosh HD 749.3 GB disk0s2ģ: Apple_Boot Recovery HD 650.0 MB disk0s3Ġ: Apple_HFS Macintosh HD +748.9 GB disk1ĬoreStorage logical volume groups (1 found) sameĬreated a recovery thumbdrive with a working copy of high sierra on another mac, booted from that, tried to do reinstall OS, did its thing, rebooted. I have a MacBook pro running MacOS Mojave.įor the past year or so, every time a new MacOS update rolls out, and is attempted to be installed on my MacBook, it ends up displaying the circle slash (Prohibitory Symbol). Rebooting still produces a prohibitory symbol. In the past, the only way I was able to get around the problem, is by re-formatting my HD, installing latest version of Mojave OS, and then migrating all my data from my Time Machine backup.ĭoing the NVRAM reset (problem persists).attempting to start in safe mode (problem persists).specifying the startup disk (problem still persists).I’m still able to boot into recovery mode ( command- R at startup), however running disk repair on my MacBook HD does NOT solve the problem. This happened again the other day with the recent Mojave 10.14.2 update. My computer automatically installed the update overnight, and in the morning, my screen was showing circle slash. This time I did some more research, and discovered that the issue may be caused by unsigned kernel extension (KEXT) files existing on my HD. Kernel Extensions are pieces of code that extends the capability of the base kernel of an operating system. The kernel typically manages Input / Output (I/O) requests, and in macOS the file ends in. Starting with Yosemite, kernel extensions must be code-signed by the developer with Apple authorization or macOS won’t load them.

Sometimes these un-signed kernel extensions cause this headache after a macOS update.

#Kext utility for high sierra software#.