Was This Clean Install?

Good day!

I tried to clean install due to issues with Sierra (wanted to revert back to old OS)
Activated erase the Macintosh HD, picked (like idiot I am) the highest erasure mode. It took 10 minutes and nothing moved... I thought I overdid, let's try again - forced shut down to begin anew. (Yes, I am an idiot...)

Opening Mac again using CMD+R, Macintosh HD was now inaccessible. I tried to recover what I could, but it was gone. Somehow I managed to change it into Apple Disk Image I think - one of the four "disks" that appears when entering CMD+R and going to Disk Utility. (Now I had two Apple Disk Images or whatever its exact name was)

I partitioned APPLE HDD and made new Macintosh HD, but that seemed to be empty.

Now I decided it was safest to just call a technician and had him install El Capitan back on and stop being an idiot.

Got my Mac back, it was like first time - appoint my admin user name etc. Those things Mac asks when you get it first time and make it yours.

I'd like to know: does this sound like clean install was done? If there was (doubt it, but just in case) malware or trojan installed, was it wiped out and system is now clean?


Rosie Moderator
Staff member
When you selected the highest erase mode, secure erasing ensures erased data can’t be recovered with a disk recovery app.
Writing over the data three times meets the U.S. Department of Energy standard for securely erasing magnetic media. Hence, it takes a long while to accomplish that.

Yes, more than likely you did get some kind of secure erase - at least a good clean install. And yes, more than likely any trojan or malware was erased.


Yes there appears to be some issue with Sierra. I bought this Mac Mini Jan 1st, and it came with El Capitan 10.11.6, and I am using an Acer (Non Apple) Monitor and it worked fine. Then I was offered the Sierra 10.12.2 update. It took FOREVER. I let it run all night, then that day one when not using it I let it Sleep, turning it off that night (Thurs) going to bed. Come Fri, when I go to turn it on, it seemed unusually long to display the start up, sigh in page, and never would. I could finally get it to, by turning it OFF & ON a couple or three times, but would go to this, "Having Trouble With Your Password," which I wasn't so hitting, "BACK" would eventually get me to the sign in page. Other than that the Monitor works fine all day, till that shut down. So ended up calling support, going to 2nd Level support, the guy being GREAT, really sharp, and having to go into a second day with him, because me having enabled that dang (@#$%%^&*) Filevault, we could not proceed.Well researching on my own, waiting for his Sat. morning call, I found others having the same or similar issue, and one person suggested resetting the, "SMC," which we had already done a couple of times, but also the suggestion of resting "NVRAM," and he said, "Sure we can try that. This is not my first computer rodeo, and as far as I am concerned, an OS re-install is a LAST resort. Had a musician friend who is a Network Engineer, would want to do one at the drop of a hat, NOT ME. Too many other things to try first. Anyway we tried that NVRAM reset, and dang it worked, the display goes to the startup sign on page immediately, and the support guy said it may just work temporarily. Well we shut down trying it the normal way, still nothing. So I had two choices, An OS re-install after I can turn Filevault off in a FEW DAYS>>LOL>>or do what I chose. I told him that I can live with that work around, doing the NVRAM reset to boot up (Command, Option (ALT WITH A PC KB), 9 & R Keys, hold them for just seconds after turning the unit on. Comes up faster than it normally did. This is a work around I can live with. The tech support concluded that my Acer Monitor is probably not compatible with the OS, so in other words had I spent all those hours re-installing the same one, it would have resulted in the same problem. Going back to El Capitan is another possibility, but the reset NVRAM is a very simple, easy work around, which I can and will live with :)