Error "DEP0001 : Unexpected Error: -1988945902" when deploying to Windows Mobile 10

Last month, I foolishly upgraded my Lumia 630 to a 650 even though I had every intention of abandoning the Windows Mobile platform after watching Microsoft flounder without hope. However, after using an Android phone as an experiment for a couple of weeks, I decided that despite the hardware (a Galaxy S5) being much better than the budget phones I typically buy, I just don't like Android. As Microsoft also reneged on their promise of a Windows 10 upgrade for the 630, I grabbed a 650 to amuse myself with.

Today I wrote a simple UWP application, which was multiple fun learning curves for the price of one, such as XAML, forced use of async/await, and of course the UWP paradigm itself.

After getting my application (a Notepad clone, a nice and simple thing to start with!) working on my desktop, I decided to see what would happen if I ran it on my phone - both the desktop and the phone are running Windows 10 Anniversary Edition, so why not.

However, each time I attempted to deploy, I received this useless error:

DEP0001 : Unexpected Error: -1988945902

Sigh. What a helpful error Microsoft! After trying multiple times to deploy it finally occurred to me I was being a bit silly. I had to enable Developer Mode on my desktop in order to test the x86 version, so it stands to reason that I'd have to do it on the phone as well. So, after doing a fairly good Picard Facepalm, I enabled it on the phone.

• Open the settings app on the phone
• Select the Upgrade & security section
• Select the For developers sub section
• Select the Developer mode radio button
• Confirm the security warning

There are additional advanced options (Device discovery and Device Portal) but they didn't seem to be required, even for debugging. And, unlike the desktop, the phone didn't need a reboot.

Now when I tried to deploy, it worked, and my application was installed on the phone. Ran it and it looked identical to the desktop version and worked fine, at least until I tried to save a previously opened file and it promptly crashed. That aside, I was actually rather impressed - Universal indeed. I was even more impressed when I debugged said crash on the phone via the desktop machine.

I decided to write this short post in case any one else was as forgetful as I, and so I switched developer mode on the phone off again so I could reproduce the original error in case there was any extra information. Bad idea, Visual Studio really didn't like that and just crashed and burned each time I tried to deploy.

After several long waits while VS crashed and restarted, eventually I uninstalled the application from the phone and tried again, and to my surprise, while at least it didn't crash VS this time, it did come out with a completely different error message.

DEP0200 : Ensure that the device is developer unlocked. For details on developer unlock, visit http://go.microsoft.com/fwlink/?LinkId=317976. 0x-2147009281: To install this application you need either a Windows developer license or a sideloading-enabled system. (Exception from HRESULT: 0x80073CFF)

Now that's more like it! Why on earth didn't it display that error the first time around? Perhaps it was because that mode had never been enabled previously, I don't know. And for the record, everything worked fine when I switched developer mode back on on the phone.

Update History

• 2016-08-14 - First published
• 2020-11-21 - Updated formatting

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