My iMac is slow - What should I do?

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Level 1

9 points

My iMac is slow - What should I do?

Hi everyone,

I have a late 2015 21.5 inch iMac. I know it is kinda old, but I really need help. This machine is nearly useless, it is so slow while on macOS. It takes ages to open the apps and it lags so frecuently. It is so slow.

What I cannot comprehend is that I also have Windows 10 in this iMac via Bootcamp, and the Windows partition is flawless. Windows is fast as a normal pc should, there is absolutely no problem at all while using Windows.

I do not really use macOS because I like to game and stuff, but I really like macOS because of the visuals and the ecosystem with my other iDevices. I have not used macOS since the last year, because it is so slow. Today I decided to check the system and man! A tortoise is faster than macOS in this iMac.

I was thinking of reinstalling the whole system, but I do not know if that will wipe my bootcamp partition. I also do not know if reinstalling macOS will wipe my macOS files and apps. I do have a lot of important information and files and I do not want to lose them.

I would really like to use sometimes macOS instead of just going straight to Windows 10, but macOS is so slow that I think I might have given up.

Any thoughts or advise? Thanks!

iMac 21.5″, macOS 11.5

Posted on Jul 30, 2021 10:53 AM

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Answer 1

Top-ranking reply

Jack-19

Level 8

46,278 points

Jul 31, 2021 9:47 AM in response to Richynauta

Notes:

No Time Machine backup - Time Machine backup not found. • It is very important to have a backup!
Runaway user process • This may go away with a restart.

However, the reason your iMac is very slow is due to the 5400 rpm hard drive. Very slow. If you use an external SSD and run macOS from that, it will make your Mac 10 to 30 times faster for storage. For more info, instructions, and what external SSD to buy, please read: How to Setup and Use an External SSD as y… - Apple Community.

Jack

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Answer 2

rkaufmann87

Level 10

148,660 points

Jul 30, 2021 10:58 AM in response to Richynauta

Please navigate to www.Etrecheck.com and download the free version of EtreCheck. Once you have you downloaded the app and installed it, please run the report and save it. This report will help us get a good idea what has been installed on your system and help us be able to diagnose what may be wrong.

When you have your report, you can attach it when you reply to this message and we can then review it and help you determine what is needed to get your system running well again.

For instructions on how to download your EtreCheck report and attach it to your reply to this message please click https://discussions.apple.com/docs/DOC-250000211

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Answer 3

rkaufmann87

Level 10

148,660 points

Jul 31, 2021 10:35 AM in response to Richynauta

The HD is the main reason the computer is slow!

You need 2 external drives.

External Hard Disk for a Time Machine backup, I suggest a OWC Mercury Elite Pro
External SSD to replace the internal (glacially slow) 5400 rpm HD. I recommend OWC Mercury On The Go Pro & a OWC On the Pro Go Power Adapter

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Answer 4

Jack-19

Level 8

46,278 points

Jul 30, 2021 10:59 AM in response to Richynauta

Welcome to the Apple Support Communities.

I believe we need to proceed with an EtreCheck report. EtreCheck is a useful App to diagnose and identify issues, both hardware and software. It is trusted by many users. Please follow the steps outlined below:

Navigate to: https://etrecheck.com and get the free version of EtreCheckPro.
Download it. It is a free and trusted app. It is often recommended here on Apple Support Communities.
Open EtreCheck, and before running the report, be sure to check “Allow full Drive Access” at the bottom of the EtreCheckPro window.
Run the report, and put it in a post, as seen here: https://discussions.apple.com/docs/DOC-250000211. We will then examine the report for issues in your Mac.

Jack

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Answer 5

Richynauta Author

Level 1

9 points

Jul 31, 2021 9:51 AM in response to Jack-19

Thanks for the response, Jack.

I get that the HDD is slowing down the iMac, but I´m very doubtful that it might be the whole issue. The HDD is exactly the same while running Windows 10 via BootCamp, and there is no lack of speed at all in that OS. Why is that?

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Answer 6

Richynauta Author

Level 1

9 points

Jul 31, 2021 9:40 AM in response to rkaufmann87

Hey guys, I've just run the EtreCheck app. Here is the generated report.

Any thoughts on what might be happening with my iMac?

iMac's EtreCheck Report

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My iMac is slow - What should I do?

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