Old iMac doing {click-click-beep} every 60 sec during sleep

To check the health of the hard drive run DriveDx and post the report here using the "Additional Text" icon which looks like a piece of paper. The macOS & Disk Utility "SMART Status = verified" only fails when the drive is near death. I've personally only ever seen this status as failed two times in 20 years. The actual health information (aka SMART Attributes) on the drive itself will give a better indication of the health of the drive.

My guess is the drive is failing. The health report is not as definitive as I would like to see, but there are a couple of clues such as the very slow write speed compared to the read speed. Assuming the DriveDx percentages are correct, then the "Throughput Performance" and "Seek Time Performance" are not good and indicate a problem. The "click-click-beep" sounds like the heads on the drive are getting stuck and these two attributes would make sense in that context. You do have 39K hours on the hard drive which is a decent amount and typically around the time I begin to see 3.5" hard drives begin to fail these days. Chances are this noise will occur more & more.

With this type of drive failure booting the iMac with an external drive probably won't work because the internal drive failure will probably begin to interfere.

JimPek wrote:

I know that magnetic 'write' is slower than 'read', and my new 2021 Seagate 2TB USB-external drive has {read / write} throughput of {6.2 / 4.1} MB/s (likely throttled by its USB port). My old iMac internal Hitachi HD is 12 y.o. technology, and currently has {read / write} throughput of {26.2 / 1.2} MB/s -- and I agree that is a very slow write-rate, but still a very brisk read-rate (for old bones). Is the slow write-rate due to aging, and a sign of looming failure? Or is that typical of 2010 tech? The 2010 read-rate is so fast compared to the UBS-throttled 2021 Seagate drive. So, I don't know. Your comments?

The speeds reported by DriveDx are not the real speeds and are always much slower than the real speed if you checked the speed using a regular drive speed check app. When reading the DriveDx report I only use the speed listed as a basic reference relative to read & write on the same drive. A hard drive's speed can be anywhere from 20MB/s to 150MB/s with most somewhere in the 40MB/s to 80MB/s. The speed can vary even on a single drive depending if you are doing the test on the inner tracks or outer tracks.

I do agree with you about the Seek-Time Performance having a status of 50% and raw value 40 (ms?), but DriveDx judges that to be 'ok'. Furthermore, the Problems Summary says all the life-indicators are ok and there are zero (!) I/O errors, and the 4 Important Health Indicators all have 100% ok status. So, DriveDx says no errors and no fail indicators...

Those percentages reported by DriveDx may not mean exactly what you think. In theory the percentage listed is a gauge of how close the drive is to the failing or warning conditions the manufacturer has set for the drive. I don't normally look at these particular attributes since the different drive manufacturers implement the reporting of these particular attributes differently so it is hard to interpret their meaning. If a computer is having issues with no other reasons for the issues and I see these particular attributes look like this, then I tend to equate them with the issue (some of it is a bit of experience with similar model of drives).

The best & most important attributes for accurately judging hard drive health (SSDs are different) are the Reallocated Sectors & Events and Pending Sector Counts with a couple other important attributes for some brands of drives. As soon as the RAW value goes above zero on these particular attributes it indicates the hard drive is failing (the % of "Value/Worst" & "Threshold" may still be near 100%, but the drive is considered bad & failing). SSDs are interpreted differently.

If these two attributes keep declining, then it would definitely be an indication that the drive is failing or wearing out whether it is caused by the hard drive itself or whether a bug in macOS is causing stress on the drive leading to premature drive failure.

I would think that my {click, click, beep} 1400x per day for months, if due to sticking (getting stuck) drive heads would generate some I/O error accumulation over time, but perhaps not. As you say, DriveDX can't give a full diagnosis, so that suspicion (sticking heads) can't be ruled in nor out.

The clicking is something mechanical and sticking heads is common. Maybe something is activating the heads to move and park repeatedly (that is not good for the health of the drive). A beeping or chirping sound from a hard drive is usually fatal.

I now wonder if the {click, click, beep} was due to a macOS bug in the iMac sleep cycle.

I use the past-tense above, because now the {click, click, beep} is gone. And I don't know why. And I can't reproduce the conditions that ever started it. Now when the iMac sleeps (display dims to black), 32 sec later is a {click} and the drives power-off and spin down (Hitachi internal & Seagate external). So, my problem refuses to manifest. Good or blah?

Sounds like there may indeed be a bug in macOS or some corrupt system preference. Hitachi hard drives had the best reputation for being reliable hard drives. It is a shame they don't really exist anymore.

HWTech, thank you for recommending DriveDx. I will buy the full version & run it in background to be alerted to looming drive failure. .... At this point, with drive silence, I'll monitor the drive and also the macOS behaviour. I also run TimeMachine as a BU policy.

DriveDx is very good at assessing the health of a hard drive so if you see any "Warnings" or "Failures" listed, then the drive should be replaced. However, DriveDx (and other drive monitoring apps) don't really assess the health of an SSD properly so a manual assessment of an SSD's SMART Attributes is necessary since a bad block on an SSD is not fatal and is expected as normal as long as only a couple blocks go bad in a short period of time.

You need to copy & paste the body of the report into the "Additional Text" field. You only pasted path to the file. These forums don't really have a real attachment tool.