Hello!
A photographer friend of mine as it is common had his important work data on a single WD blue 2.5'' 500GB drive which now has four bad blocks.

Symptoms:

If connected as master via sata3 it sometimes does load the OS(Win8.1) and after a while gives a BSOD for a second until restarting.
Disk is spinning fine, no clicks or anything funky.
BIOS and Windows does recognize it when connected via sata-usb adapter.
Explorer can't open it, shows up kind of as uninitialized. Just the drive but no volume. Double clicking it makes it think for 20 minutes until saying it can't access it.
Disk management MMC does not load.
Hirens Acronis does detect it at first, but when selecting clone option does not show it in the list.
Linux based recovery OS with CloneZilla(w/ badblock skip; w/out auto repair option) can't find the partitions on the source drive.
HDDTune Pro says there's 4 bad blocks around 20-30% into a quick scan. Performs very slowly towards the end of the scan though. It took around 5 minutes to open HDTune.

After many tries I managed to find a volume on it. Via device manager-wd drive-properties-volume-populate. I did it while HDtune was opening up and disk management was loading it took around 1 minute. It did show the volume in the properties and appeared in HDtune and disk management(3volumes in total- two of them recovery), but not in explorer. I was able to run the scan then, but still not access the data. I am attaching a pic of all info I could get at this step. Foolishly I disconnected it afterwards try clonezilla. https://i.imgur.com/HUmVtzT.png

My two last resorts are using a hardware cloning device and hoping it skips the bad blocks.
And the other is trying to get the volume visible again then using multiple software recovery tools and hope they can detect and image it.

Reaching out to you recovery experts for any ideas that might help! Thanks!
Also I'm willing to attempt learning how to disasemble it and replace a part, but don't know what could be faulty.

WD drives when have bad sectors, can become very slow due to entries in re-lo list.
Also, it might have one or more weak heads.
He will need professional tools that can clear re-lo module and lock automatic reallocation, then start to clone surface.

P.S.
Also, he should check that his computer is working fine, sometimes PCs which have not healthy power supply, can cause this kind of symptoms.
He might try to connect his hdd on another (good) pc and see how it behives.
PCs with not healthy power supply can physically damage hard drives.

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My firmware database:
https://mega.nz/folder/O01DkBRI#MxP2J6ZNqXDcrX40I8MoQQ