Catalina 10.15 and external hard drive issues

Did the drive come with any software on it and, if so, did you install that software?

How is the drive formatted and connected to your Mac?

Have you tried the following?

1 - How to reset the System Management Controller (SMC) on your Mac. 

2 - Reset NVRAM or PRAM on your Mac - Apple Support.

Log into another user account on your Mac and see if the problem persists there: How to test an issue in another user account on your Mac - Apple Support

Managed to resolve this (I hope) by following this advice from another forum on this website:

Oct 15, 2019 1:29 AM in response to alancraigmackie

I had the same issue, I have Seagate External Drive so I downloaded the "Paragon Drive" from Seagate's website and now is back to normal. https://www.seagate.com/support/downloads/

Several important points have been made that I just want to repeat:

1. many drives come with software that offer certain services. I've never found any of that third party software helpful. To the contrary, in many cases I've seen it cause trouble. Don't use it. This can especially be an issue at this time of the year - when Apple has just released a new OS. Driver level software is often broken by OS upgrades, not to mention security updates.
2. Mojave's Disk Utility may be more trustworthy at the moment than Catalina's. This is one of the many reasons I have both a Catalina installation (internal drive) and a Mojave installation (external drive) and I'll keep the Mojave installation at least until September next year.
3. external drives found at big box discount stores are often of doubtful quality. While I can recommend Western Digital bare drives, I never recommend their externals. I trust my media files and backups to OWC drives enclosures and I build my own drives.

The drives (I have used numerous) have no 3rd party software installed and were formatted using ExFAT. This problem is easily repeatable.

1. Format a drive.
2. Put the MAC to sleep without ejecting the external storage.
3. Restart MAC and drive will not be mounted.

I've tried Western Dig, Seagate and an SSD running off a simple SSD-USB interface.

There is nothing wrong with the drives in that Linux and Windows 10 can mount the drives, albeit with issues which can be fixed by the respective OSes.

Apple has screwed the pooch with this release...They cannot brush this off as being 3rd party software on devices as they state they are supported...

How is the drive formatted and connected to your Mac? Are you using the Seagate software that came with the drive? If so you should remove it as it's not needed and only interferes with the system drive management software.

Are you using the software that came with the WD drives? If so uninstall it as it's not needed and can interfere with the macOS drive management function.

It's a bit late now but for future EHDs consider either convential OWC Mercury Elite Pro external HDs or Mercury Electra 6G SSD external HDs.

When you reformat the drive you will lose all of the files on it so back it up before reformatting.

With the drive mounted launch Disk Utility and do the following:

1 - click on the top icon of the drive

2 - click on erase button:

3 - set the format and scheme to what's shown in this screenshot:

I also have problems with external drives. I have MAC 21" retina. I had WD Elements 2 TB for general storage and 1 TB used for time machine (drive which stayed after changing internal hdd drive in mac 21 retina for SSD). I had used these external drive for more than 2 years without any problems; after upgrade to OS Catalina WD Elements seems to hang up when the Mac has gone to stand by. One month later the drive stopped working and crash - I lost drive and datas. Second drive ( 1TB back up) during the working give information about unsecure disconnection and after few minutes connect again. I have bought next drive (my 2 TB was downed) - WD 12 TB My book and has started to use as 6TB which mirroring ( 6TB duplication datas) and again OS after waking up it freezes and calls for a recovery program because it works incorrectly. Sometimes it also causes the computer to not turn on or problems with shut down.

If someone have the same issues please send my what I should do?

Catalina has bricked my 2 x 4TB WD's. I've taken one out of the WD enclosure because they wont even stat up now and put it in a new USB3 one. Says it's not receivable by this computer and needs reformatting !!!!

So, Catalina has blown the power boards on both WD drives because one is now stating up but unreconisable.

How do I get it to recognise it/ Anyone?

I believe I have narrowed down my issues (Finder locking up and not being able to relaunch, and then a force-shutdown and restart being required) to my external hard drive as well.

This system (iMac 21.5-inch, Late 2013) has been rock solid for some time, along with the 2TB, 2012 Lacie drive used for back-ups and videos that is constantly connected to it.

But since Catalina (10.15.1 installed as I type this), the Finder has locked up on a fairly regular basis. I am now ejecting my external hard drive regularly, and that seems to fix the issue.

It seems like I will have to buy a new external hard drive, unless Apple somehow addresses this issue in a forthcoming update.

I keep having issues where the external drive is not recognised by the OS. Somethimes Catalina cannot Eject the disk despite there being no residual tasks shown, even checking in Terminal. The ironic thing is that my Windows 10 machine recognises the disk and that it has errors, and it then repairs it. If you let your machine go to sleep you may also encounter this issue. Hopefully you have access to a Windows machine to repair it.

It would seem that Catalina has issues surrounding externally mounted hardware!

I have found that Windows 10 will see the drives and state that it has errors that need to be repaired. I f you perform a scan and repair it seems to address the issue and it will the Catalina will recognise the drive. I use my external drive to store a lot of music samples for my music production and this is getting very annoying. i have had to repair the drive about 7 times now. Have done testing using my Windows machine and no issues. Have tried another drive on Catalina and same problems. A fix for this is urgently required!

Firstly unplug your hard drives. Catalina has blown up 2 of mine. Both WD 4T drives are ruined, that’s my TM for over 5 years and my iTunes. I was nearly sick. WD just said they aren’t supporting Catalina yet. Nothing could be done. In new caddies now and working but everything lost. Apple don’t mention this. Had to wipe the Hard Drive on my new iMac and reinstall Mojave to get stuff working again. Catalina = Vista

This is not a problem of the disk itself, but a mounting problem in the system. I have the very same problem with my SMB shares. I can mount them after a boot, but when I close my Mac, instead of disconnecting as they would normally do, finder shows the disks are disconnected, mounting point folders remain at the same place, but all are renamed to "OS X" (but on desktop the names remain the same) and I cannot get rid of them. But that does not matter, because running my AppleScript with "mount volume" command does not work anyway. The app gets stalled. This is obviously a bug and I hope it gets fixed soon.

Oh and by the way, after this happens, I cannot restart normally, but often have to force it. Also if I try to mount the volumes too soon (when not yet correctly connected to network for example), the mounting gets stalled and I have to do another restart!!! My Mac is virtually crippled right now.

This is my story too.

It took me sometime before I suspected the problem with the upgrade to Catalina.

I searched online for a solution, but it seems this is the best place I found useful information about what happened. I have all my data in my external and no backup. All data lost? Is there any solution for all?