Restart - Kernel Panic - Userspace Watchdog Timeout - No checkins com.apple.firehose.io

Hello there KSA986,

I understand you've noticed that your Mac is restarting due to a kernel panic, so let's see if I'm able to assist with this.

With your iMac, you can upgrade to macOS Monterey if you'd like to see if this resolves what is occurring. If you'd prefer to remain on macOS Big Sur, let's check to make sure there aren't any updates available to install. For assistance with either of these steps, check out the following resources. I'll also include a resource for creating a backup of information if that is needed.

Back up your Mac with Time Machine

How to upgrade to macOS Monterey

Update macOS on Mac

Once you've confirmed you're up to date, or upgraded to macOS Monterey, monitor your iMac to see if this continues. If it does continue to occur, let's work through the steps of both of the resources to see if this is cleared up for you.

If your Mac restarted because of a problem

If your Mac restarts and a message appears

Lastly, if you're still noticing that this occurs then let's reset the SMC of your Mac. If you need assistance with the steps to do this, check them out here:

How to reset the SMC of your Mac

If you're continuing to experience this, Contact Apple Support to look into this in more detail with you.

Have a great day!

Your iMac is a total mess and has a hard disk that is failing. Before you do ANYTHING back up the computer with Time Machine and verify the backup is working okay.

Next read the information below:

The best antivirus, cleaning app, and overall maintenance app for Mac OS is Mac OS itself. All you need to do with Mac OS to keep it secure and running well is to keep it up-to-date and do periodic (about 1x per week) restarts. Other than that, leave it alone. Adding third party antivirus, cleaning, security and other types of maintenance apps to Mac OS adds no additional level of security. The only thing these apps do is have the opposite affect users want. They make Mac OS slow, unstable, generate odd behavior (much like you are experiencing) and make Mac OS appear buggy.

Please locate the developers uninstall instructions for CleanMyMac and follow to the letter. Then restart in Safe Mode per the directions in Use safe mode to isolate issues with your Mac  and then restart normally.

Finally, address your hard disk problem. You can take the computer to your local AASP to have it replaced or what I'd recommend is installing an external SSD and use that as your boot drive. If performance is your top priority then get a OWC 1.0TB Envoy Pro SX Rugged Portable Thunderbolt... at MacSales.com however if saving money is your top priority then get a OWC Mercury On-The-Go Pro 1TB SSD Storage Solution and a OWC On the Go Pro Power Adapter

As mentioned earlier, please uninstall CMM, it is considered malware on these forums and does NOTHING Mac OS cannot already do. In short it is 100% worthless!

No advantage to an internal SSD vs an internal one. If you would like an internal one, that means taking the computer to your local Apple Authorized Service Provider to do the work. This iwould be expensive as iMacs are NOT designed to be worked on by end users, please leave that to the professionals. We do not recommend do-it-yourself internal repairs as it is easy to fatally damage the iMac and it is also easy to electrocute yourself by touching the power supply.

External SSDs are simple to setup and install by an average end user.

Did you ever uninstall CMM as recommended, if so please please provide a fresh EtreCheck report. If you did not uninstall, please do.

I am getting the similar error on macOS Monterey 12.2.1 and I do not have CMM installed. This started occurring after the latest OS upgrade (probably coincidental) - a few days ago!

jcb2021,

Please create your own thread. Mac OS is very stable, however KP's can be caused by many different issues and in order to address YOUR issue you should have your own thread. Cross posting when you have similar symptoms makes the OP's issue more confusing. It would be kind of like if you and I both had similar medical symptoms and both spoke to the doctor at the same time. Your issue would likely be totally different than mine.