iMac can't find the wireless printers and Sonos can't find the music library on the iMac... until I shut down, then restart using the PRAM reset, after which I can print and listen to my music. The fix appears to work for a few hours, but if the iMac is left for a while then I am back with the original problem.
running MacOS 12.6.6
iMac 27″, macOS 12.6
Since a simple reboot of your Mac doesn’t fix things, see if the problem still happens in Safe mode (press and hold the shift key down at startup). It can take much longer to safe boot (5 min) so be patient.
How to use safe mode on your Mac - Apple Support
Safe mode is non-destructive to user data. It’s not a cure-all, but very often corrects weird software behavior by forcing the OS to do cache clearing and other housekeeping. When you're in safe boot, the machine will not be at its best performance, especially with graphics, but that's expected.
Does the problem persist while in Safe mode?
Often not required, but consider allowing the Mac to "soak" in Safe mode for a couple hours to allow maintenance routines and processes time to complete, then exit safe mode by restarting your Mac normally and re-evaluate the issue again.
Since a simple reboot of your Mac doesn’t fix things, see if the problem still happens in Safe mode (press and hold the shift key down at startup). It can take much longer to safe boot (5 min) so be patient.
How to use safe mode on your Mac - Apple Support
Safe mode is non-destructive to user data. It’s not a cure-all, but very often corrects weird software behavior by forcing the OS to do cache clearing and other housekeeping. When you're in safe boot, the machine will not be at its best performance, especially with graphics, but that's expected.
Does the problem persist while in Safe mode?
Often not required, but consider allowing the Mac to "soak" in Safe mode for a couple hours to allow maintenance routines and processes time to complete, then exit safe mode by restarting your Mac normally and re-evaluate the issue again.
What happens if you do a simple restart with no resets at all? Not that resetting is bad, but you may not need it.
Maybe the PRAM battery is dead or very weak.
Internal battery of an iMac - Apple Community
Hi,
If you can, I recommend to upgrade macOS, if you can't, replace the WiFi router which could solve the problem.
The PRAM battery is not rechargeable.
Thank you. My iMac is running the latest MacOS it can and the wifi router is only a few weeks old. My MacBook Pro, sitting beside the iMac, finds the printers without a problem. As I said, I can restart and use the Option Command P+R and everything is fine, but that state of affairs only lasts a few hours.
Thank you. My iMac "sleeps" when I'm not using it. It is always plugged into the electricity supply, so I am not sure the PRAM battery will ever be taxed. A simple reset without the PRAM reset does not solve my problem, but thanks for the suggestion.
Thank you. Sadly I am getting the same problem in Safe Mode. I will try your "soak" tip and see what happens, but I am getting more and more frustrated and have started to look at a Mac Mini and 4K Samsung 28" display ;-)
Thank you ku4hx. My point was that the machine is not powered down, so I did not think the battery would come into play as the machine was always live. I could understand the PRAM requiring battery power to retain information if the machine was cut off from the electrical supply for a period, but this "glitch" occurs when the machine is on.
Anyway, my new Mac mini M2 arrives later today, so hopefully, I'll return to normal. In the great scheme of things the iMac has been in use 24/7 and it's a late 2015 machine, so I should not complain... though my MacBook Pro is an early 2011 and it is still going strong other than the fact it can't run a later version of Mac OS than High Sierra (10.13.6).
iMac loses printers and needs PRAM reset before finding them
