Dropbox Backup shows external drive not plugged in even though it is

Hi joeking1, I hope you’re doing well and apologies for the late reply, radiofc. 

If this is still an issue on your desktop apps, can you send me the app version that the Dropbox app’s running on your devices? 

Also, did this start happening after restarting your computers?

Dropbox V 171.4.6182 is the only version I could find.  Windows 11 64-Bit.

It started happening  during a sync for BACKUP... it took over 4 days for <1TB of backup from external drive to Dropbox cloud.  Have re-booted and powered down several times to clear, but doesnt help.  Computer shows the external drive as active...

Hey joeking1, can you check your backups page online, to see what if your external drive appears as active and connected there?

I've been dealing with this issue for a few weeks, too.  Windows 10, Dropbox 172.4.7555.

I have Dropbox set to backup two external drives, which are physically a RAID array of 5 drives in a NAS box and setup as RAID through Windows.

It worked fine for months, but suddenly one day a few weeks back I had to restore some files and found that Dropbox was saying to plug in the drives.  They're of course plugged in and working fine.  It had also occurred to me that some files that change regularly on those drives I hadn't seen listed recently in the recent activity shown when clicking the dropbox app icon in the taskbar.
I just found this thread and checked my backup page online per this latest post and to my surprise it -appears- that those files are indeed being backed up.  Files I changed in the past couple days showed their correct last modified date.  So that's good.

But it's still disconcerting that an app being used for important backups doesn't say or understand that it's actually working.
It'd be great to have a fix for this.

I have the same problem with my two Macs.  Running Big Sur on one and Ventura on the other.  The dropbox folder is on my computers and they sync just fine. The external drive that now is not recognized by Dropbox ("not plugged in"  even though it is plugged in) used to back up to around February 21, 2023.  The drive is a Seagate with 2Tb of memory.  I store my Lightroom files on it. I have another drive, a 100 GB Verbatum SSD which has some lightroom files on it. It partially backed up and then stoped.  Right now dropbox is trying to finish backing it up even though it has been disconnected. Note, my computers have no problem accessing both of these external drives. Both drives are formatted with an apple file structure. I formatted a thumb drive with the apple file structure and it seems to run OK on either computer with Dropbox.

Additional.  Some of the files on the external hard drive are also in the dropbox folder on the computer hard drive. Wanted to make sure they were where I wanted them in the cloud before wiping them out on the dropbox folder.  Have NTFS for MAC on one computer (Ventura), (it did not cause a problem in the past) and Paragon (does the same thing) on the other computer.  I have also encountered an error message that dropbox cannot read a file on the external hard drive. I noticed that the Seagate external hard drive is listed on the dropbox app as having many duplicates, none of which have any content.