External drive dialog box disappears

I agree P. Phillips' responses were less than helpful, however, the link does give a hint to a solution that worked for me.

I too was having the issue where it would flash for a second and then disappear. While I'm not sure how to fix that issue, I was able to workaround the issue and access the drive by going to System Settings -> Privacy and changing the "Allow Accessories to Connect" from "Ask For New Accessories" (which I think is the default) to "Automatically When Unlocked". This did allow my SD card to mount so I could access it. You could always revert back if you're concerned with security.

Hope this helps Mike and Lewis!

Excerpt from previously supplied link

Change the setting for allowing accessories to connect

By default, your Mac laptop with Apple silicon asks that you allow a new or unknown accessory to connect. To change this setting:

1. Choose the Apple menu  > System Settings.
2. Click Privacy & Security.
3. Scroll down and click the pop-up menu next to "Allow accessories to connect," then choose which option you want. Learn more about the options.

I am experiencing this too. On my system I have narrowed this down to only happening when there are two or more users logged in at the same time. I've filed a Feedback Assistant report with screenshots etc. The solution for me, beyond being very fast on the clicks, is to log out all users long enough to mount the device and then log them back in.

Was having the same issue with allow dialog only appearing for a second or less. I had two users logged in at the time. The behaviour stopped when I logged out one of the users.

Maybe this helps.

Refer to Link Below from Apple on this very topic

If your Mac asks you to allow an accessory to connect - Apple Support

Excerpt from link above

When you use a new or unknown USB accessory, Thunderbolt accessory, or SD card with your ➡️ Mac laptop with Apple silicon  ⬅️ and macOS Ventura or later,

I have the same problem, with USB drives. My way around it is to rapidly tap the "return" key immediately after plugging the USB drive in. I assume that presses an 'enable' button on the popup (which I never seen, just a short flash). After that the device is known and will connect in the future. Sometimes I miss it and have to remove and replug the drive.

I had this problem yesterday. A reboot fixed it, although I suspect that there's a bad plist file somewhere that could be removed manually to avoid a reboot.

If your Mac asks you to allow an accessory to connect - Apple Support

This is a pretty annoying bug that impacts my mac as well. I only "fix" is to unplug-replug devices until the dialog eventually decided to stay around for more than a millisecond.

Apple, please fix this.

I think you may be misunderstanding the issue. There is a system glitch where the dialog to allow an external device to connect pops up for just a fraction of a second which makes it impossible to respond or hit 'allow'. Then it disappears and the external drive will not mount. This is also happening on my Time Machine drive that ive used for years without issue. It only started becoming an issue a couple months ago.

Currently (version 14.1.2) the bug is still present, it is very annoying even if the workaround that consists to change security setting by Allways allowing to connect accessories is not a lasting solution

Generally, I do not respond to secondary User questions but as a courtesy

On 2 M1 and 1 M2 Apple ARMS based Apple Silicon computers I own and use, when new or unknown USB accessory is attached Directly to the machine the Pop up alert is presented

I have the same problem as lewis-john-walker. The Apple support article you linked is very general and unfortunately does not address this special case.

Thanks for this!! seems to be working better now.

Brilliant, saved my morning, thank you!