Is your Android mobile phone or tablet slow to use? Is it running out of storage space and memory? Are your getting error message or problems with apps crashing? The cause, at least partly, could be due to junk files cluttering up the system. Here is how to find them and delete them.

A clean up of your phone's storage could solve some of the problems you are having with a lack of space, memory and crashing apps. Removing an app from your phone should be easy and you just go to Settings, Apps or Application manager, tap the app you don’t want and then tap the Uninstall button. Unfortunately, this does not remove every file and folder created by the app and there are left-overs. Orphaned files that don't belong to anything and are never used.

If you like to try lots of apps in the Google Play Store you will end up with lots of junk files afterwards. If files remain after removing an app, they will remain forever because Android will never clean them up. Over time they will build up and they could consume a significant amount of space, which means less room for your photos, music and other apps.

If you install an app and it does not work, one of the things people try is uninstalling the app and then reinstalling it from the store. The problem is that if there are files left over from the original installation, they could trigger the same problem as before when the app is reinstalled. The app might just crash again. It is best to remove all the files and then perform a clean install.

Let’s take a look at an example. You should first read You have been uninstalling apps all wrong, which shows how to uninstall apps correctly and then how a utility like 360 Security can clean up the junk files that are remaining.

In that article I showed how to delete Waze properly and clear out the junk files afterwards. Now I will show that there are even more left-over files that even 360 Security missed.

I will be using a Samsung Galaxy S4 for this, but it will work on any phone or tablet with a fairly recent version of Android.

First pull down from the top and tap the gear icon or go to the all-apps screen and tap Settings. Select the More tab at the top of the screen and then tap Storage.

Android settings . Android settings

This displays the amount of storage space used and free. The used storage is conveniently organised into categories so that you can see the space used by applications, pictures, downloads, and so on. Down near the bottom is Miscellaneous files. Tap it to view them.

A list of files and folders is displayed and you may see some from apps you have removed. I uninstalled Waze, but as you can see there is still a waze folder that contains 40.00KB of files. Another app I no longer have is Moodlytics and it was uninstalled a long time ago. Yet there is still a Moodlytics_Backup folder in the storage.

Android settings

These folders are using up storage space. OK, it isn’t a lot in these two examples, but I try to keep a pretty clean phone and you may find much bigger folders than these. It isn’t just about the storage space though, and if you reinstall an app, perhaps to try and solve a problem with it crashing or not working properly, it will reuse the old files. Delete all traces of the app and you can perform a clean install.

Tick the box next to any item that belongs to an app you have removed and a trash icon appears at the top. Tap it to delete the selected files and folders. Take care no to delete anything you are not sure about. The two folders in the example are clearly associated with the two apps I used to have, but are no longer present.

RelatedUninstall updates to fix problems on the Samsung Galaxy

It may seem that you can removed everything, but once more there are hidden files that are lurking in the storage. Browsing the storage using Android's file browser as described above does not show everything. To get the whole picture you need a file manager app. There are lots of them in the Google Play Store and many have 4+ star ratings. The are all good. I chose File Manager, but you could use another tool.

 Browse the internal memory of the device and you will see the folders belonging to apps you have installed and apps you have removed. In addition to waze and Moodlytics, I also found viewranger, an app I was playing around with recently, but then uninstalled.

File Manager for Android

Long press on an item and it is selected. Other items can then be tapped to add them to the selection. A trash icon appears at the top and can be tapped to delete the items.

File Manager for Android

Go back to the second screen shot, which shows the storage categories. It says that there are 242KB of downloads. Tapping Downloads does not display them and instead it says that there are no downloads. Open the Downloads folder in File manager however, and it shows that it contains a subfolder and it is this that contains the 242KB of downloaded files. It seems that the Android file browser only shows files in the Downloads folder and not subfolders. This is another reason for using a file manager utility.

File managers are great tools for expert users, but if you don't know what you are doing, you can cause problems. Take care.