External Hard Drive seen by disk utility but not by Finder

I had the same issue.

The solution is to go into disk utility and click 'mount' for each partition that is not showing up in Finder.

I had the same problem with more that one external USB drives. I tried the SMC reset to no avail.

Here's what did it for me.

Make sure that the Finder Preference menu shows that Drives, etc. are shown on the Desktop. Then drag the disk icon of the problem drive from the Desktop onto the side bar of the finder.

Don't know why this works but things seem to be normal afterwards.

I had the same problem with more that one external USB drives. I tried the SMC reset to no avail.

Here's what did it for me.

Make sure that the Finder Preference menu shows that Drives, etc. are shown on the Desktop. Then drag the disk icon of the problem drive from the Desktop onto the side bar of the finder.

Don't know why this works but things seem to be normal afterwards.

My external hard drive can be seen by Disk Utility but not by Finder.

Finder menu > Preferences... > General

"Show these items on the desktop" > Hard disks > select.

Also, desk utility says the hard drive is full.

Where do you see that? A screenshot may be helpful: How to take a screenshot on your Mac - Apple Support.

Please reset that Mac's SMC: Reset the System Management Controller (SMC) on your Mac - Apple Support.

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It shouldn't matter. When I had that problem I disconnected the USB hard disk drive before performing the SMC Reset, so that's what I would do. It was only necessary to do it once, after that external hard disk drives reappeared every time.

You can connect it before starting your Mac, or after restarting it and logging in. That definitely doesn't matter.

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Doesn't matter. Unplug whichever end is more convenient.

Do you need that external hard disk drive to work with Windows PCs as well as your Mac?

If yes, then it needs to be formatted with Disk Utility's Erase function. Choose a compatible format, such as ExFAT.