Safari is not working on my iMac

Please restart the computer in Safe Mode (NOTE: A Safe Mode restart may take up to 10 minutes so please be patient) and then restart normally and test.

Also, by chance do you have any of the following types of third party apps installed on the computer:

1. Antivirus
2. Cleaning
3. Security
4. general maintenance
5. VPN

If so, there it is VERY likely those installations are the cause of your problem.

See Note 2 below:

Give this a try: boot into Safe Mode according to How to use safe mode on your Mac and test to see if the problem persists. Reboot normally and test again.

NOTE 1: Safe Mode boot can take up to 3 - 5 minutes as it's doing the following; 

• Verifies your startup disk and attempts to repair directory issues, if needed

• Loads only required kernel extensions (prevents 3rd party kernel/extensions from loading)

• Prevents Startup Items and Login Items from opening automatically

• Disables user-installed fonts 

• Deletes font caches, kernel cache, and other system cache files

NOTE 2: if you have a wireless keyboard with rechargeable batteries connect it with its charging cable before booting into Safe Mode. This makes it act as a wired keyboard as will insure a successful boot into Safe Mode.

Your welcome, it may also be wise to do the following:

It will help us get a good idea of what is causing your problem if you provide a report of your system, that way we do not have to play 20 questions with you. The report we are requesting does NOT provide any personal information and is extremely safe to use. 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 How to use the Add Text Feature When Post… - Apple Community It is helpful to us if you download the report to your Desktop.

The first thing I noticed is that you have the second slowest iMac Apple offered at the time of purchase.: 4 GB RAM, an i5 CPU and a 7200 rpm hard drive.

The Flash Player poses a security risk and should be uninstalled. There are no website using Flash so it's not necessary.

Unfortunately the RAM is not upgradeable unless you have an Apple Authorized Service Provider do the work. However, it would cost more than the iMac is worth.

One way to help performance would be to get an external SSD, clone your boot drive to it with Carbon Copy Cloner and boot and run from the SSD.

That could speed up your read and write speed about 5x or more. It currently is

Write speed: 89 MB/s

Read speed: 102 MB/s

This setup I use in a 2017 iMac to boot older systems from to use older software:

I get around 450 read and write from it. However it would not help Safari. It would need more RAM. I have some problem with Safari with 16 GB of RAM if I have many windows/tabs open at the same time. How many do you normally have?

You do have a lot of apps in the User Login Items and any that you can launch when needed and then close would help with the performance.

You'd be better served saving up for a new Mac.

Please read the directions carefully for Safe Mode. If you are using a wireless keyboard either plug it in using the charging cable to the back of your iMac or use any wired USB keyboard. Then shutdown the computer and restart while holding down the Shift Key and continue to hold the Shift Key down until it restarts in Safe Mode.

Adobe Flash Player is installed and was obsoleted by Adobe years ago. This is also a security threat to your system and needs to be addressed ASAP. Please navigate to Adobe's site to find the instructions to uninstall Flash correctly and follow them to the letter.

Also, some clarification please. You mentioned Safari doesn't work on your system (which is quite ancient you know!!!) what do you mean exactly? Are you saying Safari does not launch at all? If so then restart in the Recovery Partition and do an install Mac OS. This type of install does NOT write over any of your data. What it does is fill in missing or damaged parts of Mac OS. I suspect this may help.

If you can get Safari to launch however it will not open some websites you try to visit that means that your have a VERY old system and you either need to get a new(er) Mac with a later version of Mac OS or use another browser.

Firefox should be fine, Chrome is a major resource hog and should be avoided if possible.

Mac OS does not require additional security apps, simply keep Mac OS up-to-date and restart the computer about 1x per week and it should be fine.

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Do Firefox and Chrome work ok?