Using External SD Card with Google Play Music App
Update 5th Dec 2013: Today an update to the Google Play Music app has added a new feature in the app’s settings, allowing you to choose to store files on the external sd card instead which solves this problem.
Context:
I use Google Play Music as my main media player because I like having my music stored in the cloud and the Google Play Music App is pretty good.
The Problem:
On a device with both internal and external storage such as the Motorola Photon Q, the Google Play Music android app will only store files it saves for offline playback to the internal storage.
This is a real problem since most devices with this configuration have a relatively small amount of internal storage (8 gigs usually) which even a modest music collection will fill up quite easily. This is not only a pain since you can’t cache all your music, but also means that you have run out of space for anything else such as installing more apps.
The Solution:
Create a couple of sym-links from the internal storage to the external SD card.
Prerequisites:
- Your phone must be rooted.
- You must have a terminal emulator installed.
- You must have a file explorer app installed.
- You should know what a terminal is.
- Read here to learn what a sym-link is.
Steps:
- Go to Settings > Applications > Google Play Music.
- ‘Force Stop’ the app and clear all app data.
- Open your file explorer of choice and create a directory (folder) on your external SD card called ‘GoogleMusic’.
- Inside this directory create two more: ‘files’ and ‘cache’.
- Open terminal emulator and enter the command: su –
- The superuser app will ask you to grant root privileges. Hit ‘Allow’.
- Enter the following commands in order:
- cd /data/data/com.google.android.music
- ln -s /mnt/external_sd/GoogleMusic/cache cache
- ln -s /mnt/external_sd/GoogleMusic/files files
- You’re done!
Charles Wilkinson 
Works perfect, thank you.
I was able to keep my music without having to download again.
Using ES File explorer (any file explorer should work as long as long as it can explorer root), I copied the 5 folders from inside data/data/com.google.android.music to my new GoogleMusic folder on my sd card. Next, I cleared cache and data for Google Play Music. Then ran the “ln -s…” commands above using the appropriate folder names for each.
ln is lower cased LN.
I had to use a different path for my external sd card. Rather than “ln -s /**mnt/external_sd**/GoogleMusic/cache cache” I had to use “ln -s /**extSdCard**/GoogleMusic/cache cache”
These are the 6 commands that I ran, each individually, and they are case sensitive:
cd /data/data/com.google.android.music
ln -s /extSdCard/GoogleMusic/databases databases
ln -s /extSdCard/GoogleMusic/app_sslcache app_sslcache
ln -s /extSdCard/GoogleMusic/files files
ln -s /extSdCard/GoogleMusic/shared_prefs shared_prefs
ln -s /extSdCard/GoogleMusic/cache cache
Oops extSdCard, not extDsCard…