Soon after I installed the Windows Phone 7 ‘NoDo’ update (see my previous post), another update pops up. This time, instead of a functionality update, this one is more concerned with replacing some fraudulent web certificates (more details here).

WP7 Certificate update prompt.

Sounds like a good idea. However, before the update process can get into gear it abruptly stops with a disk space related problem. Those of you that have been following my blog will know that I’ve been going through space issues of late (see “How to turn a physical disk to a bootable VHD”) and so my laptop is creaking at the seams (only through my own laziness).

WP7 update error on backup 

This time, to install this update I’m going to have to free 1.1GB on my C:\ drive. What happens on the next one? (the current expectation is that Windows Phone 7 settings in Zunethere is a bigger, functional update being crafted together by Microsoft called the “mango update”). With the minimum memory  specification for Windows Phone 7 set at 6GB it would appear that I could be asked for another 6GB on the next backup and my C:\ drive will surely groan, however can’t I push these backups onto my other logical “data” disk?

The logical place to look at first is at the Zune software which handles all the syncing of data between your computer and the phone device. I know that there are a good number of settings to help configure the music and video library, plus temporary folders where conversion files end up, however there is no sign any setting that allows control of backups.

I’ve also done a search of the registry hunting down the Windows Phone 7 and Zune registry keys for a hint of the directory. Nevertheless there’s nothing of interest there. (Note: if you’re not old enough to know about the registry, then leave it alone because playing about in there without confidence is lead you to disaster).

After a bit of head scratching, one of my disk analysis tools came up trumps and I discovered the following folder:

Windows Phone 7 backup folder

Of course, this folder existed since I had to perform a phone backup as I installed the “NoDo” update a couple weeks ago (see my previous post). As you can see, it’s in my AppData folder which is governed by the operating system as part of the profile store. Sigh, that means that I have to do some substantial reconfiguration of my Windows 7 instance to remap my AppData folder to a disk with ample space. I don’t want to do this.

Thus, I’ve resorted to an old trick that I used to play when configuring servers with small disk partitions in the late 90’s. Before I divulge this tip, let me warn you:

NOTE: I don’t assume any responsibility for your backups or stability of the system. It’s your computer and your choice if you follow the guidance below. The old adage that it works on my machine is not a guarantee that it works on yours!

Swap out folders – basically take a copy of the files, park them up somewhere else and label it up so you don’t forget. If you need to restore the backup later, then just move the files back as you need them! Thus:

  1. Locate the folder C:\Users\<your username>\AppData\Local\Microsoft\Windows Phone Update
  2. Copy the folders within, to a different drive and backup folder of your choice.
  3. Delete the contents of each sub-folder of the Windows Phone Update folder. By leaving empty patch directories, you’ll have a chance at remembering what goes where if you need to restore later.
  4. Create a shortcut to the backup folder and put it in your Windows Phone Update folder. Rename this shortcut as “Windows Phone Update – Backup Location” (easier if you have two windows explorer windows open).
  5. Create a shortcut to the Windows Phone Update folder and put it in your backup folder. Rename this shortcut as “Windows Phone Update – Original Location” (easier if you have two windows explorer windows open).

Therefore, you should end up with something like this:

Windows Phone 7 moved backups

If you ever did need to revert back to a particular backup set, it’s easy enough to copy the folder to the destination at the end of the shortcut! Voila!

A couple of other pointers to make your backups a bit lighter:

  • Most Windows Phone backups are full device backups, thus all the internal operating system, settings and content is copied off the device. Depending on your usage, (and mine has been making good use of the video playback on my HD7’s big screen) regularly discarding unwanted videos, music or games does help reduce the amount of data to backup.
  • Backups can be placed on any drive you like, but if it is a Windows formatted disk, make use of the folder compression options. Granted, that the compression rate may be pretty low because a Windows Phone 7 backup consists of a lot of 4MB binary files, but this is still best practice and may squeeze you a bit more room. So, right click the folder and click the Advanced button on the General tab. Ensure that the “Compress contents to save disk space” is ticked.

Folder compress


I hope you found this useful. It’s certainly allowed my disk to breathe until the next phone update!

This is a cross post from my EMC blog, mainly for backup duplicity and to aggregate some of my past postings. My EMC blog used to be under the Conchango brand but was acquired by EMC so I’ve also retrospectively refreshed some of the old links and maybe a tweak a bit of content too.
permalink to the original post here