Parallels incredibly slow on Intel iMac Sequoia 15.5

I have a similar issue with my 2019 iMac 27". I'm using PLL 18 and windows 10. I see the Creedence drives in the disk utility panel but not on my desktop. In my case all runs fine as it appears the Creedence discs are not impacting any operation. I believe the Creedence discs are rated to Sequoia on Intel Macs. Not sure how to permanently remove from desktop unless you select to not show drives on desk top in the Finder settings. Not sure why your performance is slow.

Look at this discussion. One person removed by logging out of iCloud and then back in.

4 disks called "Creedence Cryptex" appear… - Apple Community

It's interesting to see Creedence drives after updating to Sequoia. I do NOT run Parallels, but I see one disk image of size about 4.2 MB (not GB) device with a synthesized APFS container inside. Names like Secure PKit Trust Store suggest it has to do with some newly added secure credentials.

Like the crypto-locked virtual System drive, that Creedence drive is NOT shown in Finder and is NOT present in the /Volumes directory

That is also not the source of your slowness.

What macOS were you running before?

I am running Parallels Desktop Pro v20.4.0 (current) on a 2020 3.8 Ghz Core i7 iMac with 40 GB RAM. All of my guests are stored on an external Crucial X8 USB 3.2 Gen 2 SSD that is directly connected to one of my Thunderbolt 3 ports. Because I have the Core i7, it has 8 discrete CPUs with Intel Hyper Threading support for a total of 16 potential processing threads. Your Core i5 has six discrete cores, but no hyperthreading support.

My Windows 11 Pro (24H2) guest is configured to use 8 processors and 8 GB RAM. I have allocated 64 GB to the guest container that reclaims disk space upon shutting the guest down. It launches and runs briskly.

My Ubuntu Linux 24.04.2 LTS guest has 6 processors and the same 8 GB RAM assigned to its 26 GB container. It also launches as fast as if on bare metal.

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Whatever operating system you were running earlier, Sequoia is larger and more resource hungry. That will have a telling effect on your Parallel's guests with inadequate RAM or processor cores assigned to them — especially on an iMac with 8 or 16 GB RAM.

You need to ensure that you keep current with the Parallels Desktop versions. Do not assign all of your available Mac RAM or processors to the guest. If your iMac has 8 or 16 GB RAM, and is a 27-in model, then I would encourage you to raise the RAM to 32 GB via a compatible purchase at macsales.

If you installed the Parallels guests into a folder on your internal Mac drive, any changes to these guests will cause Spotlight to index them and Time Machine to include them in a backup — unless you excluded them in Time Machine and Spotlight. Backing up these guests will be a slow proposition which you will feel.

Unless there is some overriding reason to keep running Windows 10, you might consider upgrading to Windows 11. Licenses for Windows 11 can be had on the cheap at StackSocial dot com.

DavidDawson wrote:

multiple "Creedence Cryptex" disks showing up on the desktop

That disk image is AFAIK part of macOS and can be ignored. But for some reason it annoyingly auto-mounts for some users. Do you really have multiple such images auto-mounting?

https://eclecticlight.co/2025/07/09/cryptexes-ai-and-creedence-clearwater-revival/

Regarding slowness, do you have any 3rd party virus apps or "cleaners" that are infamous for corrupting the system? An EtreCheck report would eliminate much guesswork:

Using EtreCheck to Troubleshoot Potential… - Apple Community

DavidDawson wrote:

I've checked to make sure Parallels is up-to-date and so is the iMac. Any ideas of what's ruining the performance? Is the performance and the appearance of DMGs related?

How much RAM do you have?

Related question: Is that a 27" iMac (where adding more RAM is easy), or a 21.5" one (where it involves tearing apart and then reassembling the entire computer; a job best left to a repair shop)?

We kept installing updates ever since we bought the 2019 Mac and it works a treat still on sequoia 15.5 on the apps we use but only after it has been left alone for over 10-15 mins booting up. Such a strange thing to need but then still work. why is that? Oh and because we can't take the machine apart to install extra RAM, have got by on intel i5 3Ghz 6 core with only 8GB of RAM. figure that one out!

Also, remarkably , I'm installing Sequoia 15.6 tonight.

The catch has been after each update to run disk utility and also spotlight indexing afterwards and every so often and trying to clear caches and safe boot from time to time.

On Activity Monitor the intel processor is hardly ever maxed out, or the memory..it's more likely the disk!

<< have got by on intel i5 3Ghz 6 core with only 8GB of RAM. >>

[in my opinion] a Mac with only 8 GB of RAM does not have enough RAM to run Ventura or later in an appropriately-responsive way. To use it that way, users often have to completely QUIT one App before launching the next.

You are several versions and beyond the last MacOS that can run acceptably well in 8 GB.

Now, on top of that, you are loading Parallels and an ADDITIONAL Operating System. Of course it slows to an unusable crawl, and takes many minutes before the paging/swap onto and off the disk calms enough to be marginally useful.

You need a computer with MUCH more RAM to do the stu.ff you are attempting.

-OR- you could try retreating to Monterey for a very slight improvement.

Some related reading, and some theories: https://apple.stackexchange.com/questions/476879/why-does-my-mac-show-a-strangely-named-volume-credence-and-cryptex-after-updat

👍🏽

would be interested in differences with 32GB. may buy a Mac mini and new screen otherwise.