I was just checking Twitter before work this morning and suddenly I get a little pop up saying "Installation complete". It wasn't in the notification bar but a little message at the bottom of the screen (like when it tells you you've connected to a wifi connection). Thought this was a bit odd as I hadn't downloaded or installed anything, so here's what I did: - Checked 'My Downloads'. Nothing out of the ordinary in either 'internet downloads' or 'other downloads'. - Checked the download folders in both the stock browser and Firefox (which is my default browser). Nothing in either. - Checked to make sure 'auto-update apps' wasn't checked in the Play Store - it wasn't. - Checked my 'downloaded applications' and nothing out of the ordinary there. Also checked through the application manager, and again nothing that shouldn't be there. - Checked 'About Device' to see if a software update had auto-downloaded but it doesn't appear to have. Now I have Avast on my phone and have it set up to check apps for malicious content, both on installation and whenever an app runs, and that hasn't given me any warnings. The only thing strange I DID notice when checking Avast was when I checked my data usage I noticed 'Download Manager' has downloaded 4.5mb data this morning. It's also used 147.8mb this month, so I don't know if today's usage is normal or not? Is there anything else I can do to check what it could have been that installed? I'd rather not have to do a factory reset if possible, but will if it looks like my phone's been compromised somehow.