iMac Unusably slow after High Sierra Upgrade

I am having a similar experience. Got OSX on one partition, windows bootcamp on another. Only OSX is running painfully slow, while windows is normal. I reformatted and reinstalled latest OSX, it is still slow. I have tried resetting PROM PRAM, didn't work. Checked if the disk had any bad bits(?), it was fine. How can a fresh OSX still be slow when windows is normal?

I will see what I can do regarding EtreCheck. It's been a while since I put it away, I needed OS 10.8 to install Etrecheck. Upgraded to Mojave, which took about 48 hours. Then I tried to log into the AppStore, but it kept complaining about username/password, even though I tried several times and made sure it was correct. Not sure if I am gonna bother any more with this as this macbook is sabotaging every move. Even typing letters is a few seconds on each.

Even though the situation doesn't make sense to me, my main suspect is that the OSX partition on the PCIe disk is corrupted.

best wishes

I did all that. No help. My iMac has moments of clarity, then slows down to being essentially unusable. I reboot every day to catch a few moments of functionality.

I also looked for malicious software using Malware Bytes and Drive Genius.

Bear in mind that I have High Sierra on a 2011 iMac. Apple now says High Sierra is compatible with iMacs after mid-2012, so I am stuck.

The guy at the Genius bar suggested wiping the hard drive and re-installing High Sierra. Good thought, except ...... what if the problem is the incompatibility between by 2011 iMac and High Sierra?

Also, I can't make a bootable external drive, because Terminal recognizes that my installer for High Sierra is not usable.

I would like to know how to take that last shot of wiping the hard drive and reinstalling High Sierra.

Garrrr. I yield on the compatibility point. Thanks for paying close attention when I should have.

So here is my real problem. When trying to make a bootable external drive with Terminal, I have downloaded the installer [which actually works] and type in a command like this.

sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/BootableInstaller --applicationpath /Applications/Install\ macOS\ High\ Sierra.app

I get this message back:

/Applications/Install macOS High Sierra.app does not appear to be a valid OS installer application.

Do you have advice for me about getting past this error?

By the way, I looked at Console [thanks again] and see this repeatedly. I'm not sure what it means.

default 13:41:00.424830 -0800 opendirectoryd getpwnam failed with result Not Found

default 13:41:00.425913 -0800 opendirectoryd getpwnam failed with result Not Found

default 13:41:00.426726 -0800 opendirectoryd getpwnam failed with result Not Found

default 13:41:01.069460 -0800 opendirectoryd getservbyname failed with result Not Found

default 13:41:01.137081 -0800 opendirectoryd getservbyname failed with result Not Found

default 13:41:01.137535 -0800 master fatal: bind fe80::1 port 25: Can't assign requested address

default 13:41:01.512670 -0800 trustd cert[2]: AnchorTrusted =(leaf)[force]> 0

default 13:41:01.520151 -0800 trustd cert[2]: AnchorTrusted =(leaf)[force]> 0

default 13:41:01.527359 -0800 trustd cert[2]: AnchorTrusted =(leaf)[force]> 0

default 13:41:01.534634 -0800 trustd cert[2]: AnchorTrusted =(leaf)[force]> 0

default 13:41:01.541904 -0800 trustd cert[2]: AnchorTrusted =(leaf)[force]> 0

default 13:41:01.549094 -0800 trustd cert[2]: AnchorTrusted =(leaf)[force]> 0

default 13:41:01.556446 -0800 trustd cert[2]: AnchorTrusted =(leaf)[force]> 0

default 13:41:01.563856 -0800 trustd cert[2]: AnchorTrusted =(leaf)[force]> 0

Good question. I downloaded it, most recently last night, from the page you pasted in.

It's 22 MB in my Applications folder, although I keep hearing it should be 8. When I right-click on it, I see the resources folder which contains the createinstallmedia file in it. I build the Terminal command by dragging the files into the command line.

I moment ago, I double clicked the install macOS High Sierra app, and it's running now - 44 minutes to go.

Ha. I see now. Yes. The web site says 4.8 GB, exactly as the graphic you pasted in. After I download it, the install starts, and I quit. Then the "install macOS High Sierra" app in my applications folder is 22.7 MB

Umm. I ran the installer about an hour ago, which deleted the installer from the Applications folder. I downloaded it again. The image is for the version I downloaded a few minutes ago.

That page is the only place I have found the download. Can I look somewhere else.

Out of curiosity, what difference does it make to have a 4.8 GB version or the 8.4 GB installer? The smaller one runs the upgrade as it is.

Sorry 8.4GB was a mistake on my part... remembered 4.8 as 8.4 :O

I wonder if the link down at Go to Mac App Store works different?

https://support.apple.com/macos/high-sierra

I mean it looks the same, but???

Hmm. I tried my version of the installer in the terminal command line. Same error -

"/Applications/Install macOS High Sierra.app does not appear to be a valid OS installer application."

I deleted the 22.7 MB installer in my Applications folder, followed the link you gave me which took me back to what seemed to be the page corresponding to the screen capture I sent before. I downloaded the installer, which looked familiar, and ran the command in Terminal - same error.

Here's a thought. What if I used my laptop to build a boot drive? Will that boot drive work on my iMac?

Say. I'm ready to get dinner. You have been super helpful and I really appreciate it.

A couple more thoughts.

I read the suggestion of replacing my hard drive with a solid state drive. What do you think about that? When my iMac is sluggish, I hear the hard drive pounding away like mad.

Second, thought - what about asking the Apple store to make me a boot drive? Maybe they have a secret page for downloading a different installer.

I'm sure the Apple Store has the installer, whether they'll help I'm not as sure of, but I'd ask.

My feeling on SSDs is that they only help at Startup, or if you don't have enough RAM & the OS needs to use Virtual Memory on a Drive. Of course if you have something ill going on & it's trying to read or write something or streaming error logs to the drive, then an SSD would make it faster.

Roughly Speaking, SSDs are 5 times as fast as Hard Drives, but RAM is 5 times faster than SSDs.

I off to eat also. :)

Is there any way to know if apple slows down their older iMacs for some "scientific" reason... something like in the case of older iPhones?

alpacas09 wrote:

What an incredibly patronising answer. Not helpful, just irritating.

Possibly, however it's frank, factual and correct!!

See my response to alpacas09 above.

But what if you don't have such software and it still runs unbelievably slow? How do I fix it? Go back to last issue?