I'm not experienced when it comes to troubleshooting and would be very grateful for some help. Long read, but hopefully the detail will help. Late-2012 Mac Mini, 500GB HD with 300GB free, and Crucial 16GB RAM. The only attached peripherals are a wired Apple keyboard, and dual monitors. Perfectly happy little machine until last week, when we upgraded from 10.14.2 to 10.14.3 After the upgrade, it was unusable - 40 seconds or more between clicking an icon and anything happening. Same behavior whether logged in as main user, or guest. Really sluggish. Safe mode worked fine though. Unable to find a cause, we used time machine to restore to the day before the upgrade, so we put it back on 10.14.2, and left it overnight. In the morning I found that it was now out of disk space! (It had eaten all 300GB of free space, leaving a paltry 11MB remaining, which it continued to try and eat). Unable to do anything with it at that point, I re-ran the Time Machine restore again, and this time logged in as soon as it was done. In 5 minutes after booting up, there were over 4GB of disk writes according to Activity Monitor - it is eating space again. Turned off iCloud, unchecked all Spotlight indexes. No change. When I sort Activity Monitor by disk writes, nothing in the list comes anywhere close to 4GB written since restart. So whatever's eating disk space isn't visible to me as a process. You can hear the drive working all the time. In Console, I identified a log that is out of control. The log at /var/log/DisgnosticMessages is writing several lines per second. So I think I found the culprit. It's a file called "2019.2.18.asl" and most of the entries are under a process called "ReportCrash" By repeatedly clicking to clear the log, I seem to be able to contain the HDD growth, but if I don't do that, I'm going to run out of disk space again. In the course of troubleshooting, I have run Repair Disk on the HDD from Recovery Mode (No errors found) and I have swapped the several-years-old Crucial 16GB Ram with the original 4GB. Also performed the PRAM/SMC reset. No improvement. If you made it this far, thank you. I'd welcome any advice as to my next move - I'm not well versed with the inner workings so not sure what to try next. It sees light use as a web browser mostly, so the only 3rd party software I think it's running would be Adobe's PDF reader.