try a different brand wireless keyboard + mouse

try a Bluetooth keyboard + mouse

I suspect errant RF

We have the same problem with brand new latitude 5520 with dock and wireless keyboard and mouse. Dell Support wants us to reinstall windows. It's a random problem that cannot be replicated, so you also will never know when it is really fixed. So I will be replacing them with old fashioned corded keyboard and mouse.

We also have the same issue with brand new Windows 11 Optiplex PCs with Dell Wireless Keyboard and mouse sets.  I have had to order replacement wired keyboard and mice and will be returning the wireless ones to Dell for a refund.

Same problem here with a brand new OptiPlex 7090 and the included cordless mouse and keyboard.  Problem went away for a couple of months after new batteries, then cropped up again today. Swapped out with corded and will see how it goes. A wireless peripheral sending the key code for DEL when batteries are low is a terrible failure mode.

We have had the same issue, it has deleted a full mailbox for a user and data when someone was working on a server.  It is the DELL KM5221W keyboard and mouse set.  We have had this happen on x3 different keyboards.  We have also experienced really poor battery performance.

DELL will replace them but are NOT acknowledging this is an issue.  We have stopped buying these after having to restore mailboxes from backups after the delete key seemingly got stuck, although it is not stuck.  Only immediate fix is to unplug the USB adapter.

This is happening intermittently with our wireless Dell keyboard/mice combos as well. To the T. Text backspacing/deleting itself and emails randomly deleting themselves unless you get out of Outlook quickly.

It's not a stuck key, it's not a battery or driver issue, it's happening to multiple users- all who have these combos, it's not a remote user, and it's not a rule that is set to delete emails. 

This is happening to me on mi G3 Dell Laptop and I do not use any additional keyboard or mouse. I reset the computer to factory settings, I changed to the new Windows, uninstall and re-install Office 365 and nothing works. Of course, Dell is not helping due to the guarantee expiration. Any other suggestions to fix this? 

We are facing similar issues as well, we are using the KB500 & MS300 combo on Windows 11 laptops.

Emails get deleted randomly and sometimes the cursor would move by itself. We tried to format the OS and even connected the same wireless kb&mouse on a HUAWEI IdeaHub device and the same thing happens. No response with Dell and I am not sure if we should change this model. I have around 400 pcs in stock and so far we have returned around 20 of these.

I had the same issue and even the warranty replacement had the same problem.   

As a business owner using ONLY Dell products I have now made it company policy to stop buying DELL.   I've  spent too many hours restoring from backups and trying to work out the human error problem ( which is what we thought it was).     DELL "  you should have acted and recalled the product"