USB and external hard drive not recognized after updating to MacOS Catalina

I took my MacBook to an Apple technician at an Apple store and had him delete Catalina and revert me back to Mojave MacOS. Thankfully that has worked, and my system is generally operating properly now. I couldn’t take the frustration of Catalina crap any longer!!

SWITCH THE CABLES! I Just updated my 2015 Mac last night and my G-drives didn't show up anymore. Well, 1 did, 2 didn't. The 2 that didn't show up were running on Thunderbolt cables into the iMac.

I changed the cables to 3.0 USB's and they were discoverable again.

i had the same issue. i've tried restarting, resetting SMC. all din't work. then i tried disconnecting the usb and reconnecting quickly. it worked for me. try it a couple of times. hopefully it works for everyone

Hello

I tried this but it made no difference.

I had this problem when I bought my brand new very expensive Mac Book pro a few months ago, it came with Catalina and has been so full of issues, this being the most frustrating one!

I am a video and photo editor and so I cannot begin to describe the time and frustration this bug is causing me. I cannot upload files to clients, sites or transfers from my ext drive (WHERE EVERYTHING IS LOCATED). Everything has to first be dropped onto my desktop and then uploaded from there! The desktop which is now telling me that it is full, because it is not a normal desktop oh no, it is linked to iCloud and I don't know where the std old desktop option went!?

Another ploy from Mac I suppose to get you to upgrade the cloud space. Nice one. When did Mac stop making expensive but useful products and start making a monetised series of hurdles to force its consumers like rats into buying more unnecessary add ons and extras.

The simple work flow has been replaced by a barrage of headaches and owning this new Mac has been more of a hinderance than help!!

Yep - after updating with a recent Catalina patch, one of my Verbatim external HDs wouldn't mount, yet Disk Utility could "see it".

I've read lots of advice re this problem on the net and here too, but nothing would work.

Finally, I linked it up to an old Mac Book Pro running High Sierra. It mounted straight away!

So I erased it and finally, my iMac running Catalina recognises it.

No idea why this would happen, but at least I can use it again and haven't lost any irreplaceable files.

What 3rd software are you using? Sorry what is a NTFS?

I wonder if apple can see (or care about) a bunch of it's customers discuss how they can get a simple USB to work.. how embarrassing.

NTFS is the file format for Windows— Mac can r/w with the updated software:

Tuxera Microsoft NTFS for Mac by

Paragon Microsoft NTFS for Mac | Paragon Software

I can get one of my external HDDs to show up on-screen at a time, but not both. USB via Apple purchased adapter. Not both at once, but at least not neither at all.

I had the same issue. I just restarted my Macbook Air and the external disk was recognized. Hope this helps someone.

I use paragon NTFS, and it can't see the external HDD after installing Catalina, and the HDD works on 2 others direct Windows PCs

Restart didn't work for me. I have a Pluscom external drive. It must be ten years old but, after all, it is for storing stuff.

Thanks, Sharmar7,

with joy I can report that the instructions on your link to RESET THE NVRAM !!!!WORKED!!!! For any readers who are as lost as me, the Options key is marked "alt" on many keyboards.

Same issue here.. : (

We bought such expensive computers, problems like that should never happen.

Reseting the Nvram didn't work for me.

Nothing worked actually.

I finally was able to get this resolved and got my Seagate backup plus drives mounted AFTER I downloaded the new Paragon NTFS driver. It has to be updated to version 15.5.x

This did not resolve my issue. However, I am on an iMac. Any suggestions would be great.