Question: When I compose a new message in Gmail on my Android phone I'm offered several suggestions for the recipient (i.e. for the email's To: field) via an autocomplete function. These are often very old/unknown contacts which I'd like to no longer see as autocomplete suggestions, but I can't yet work out how to clear this list. 

The contacts suggested appear to have come from an old list of "Other" contacts, i.e. people that I've contacted infrequently and who were not actual contacts I've added to my contact list. These only show up when I compose a new message in Gmail on my phone, and the autocomplete works as expected when on a non-Android device (laptop).

My assumption is that the Gmail autocomplete function is reading these outdated contacts from a list stored somewhere in a file on my phone which is impervious to the contact sync process or somehow not being cleared as expected otherwise -- I've tried all manner of syncing phone contacts, deleting old/other contacts outside of Android, etc. but no joy so far.

An idea I have is to somehow search Android's filesystem for a file that contains the unwanted contacts and if found then wipe that file clean. Is this reasonable, and if so can anyone suggest guidance that'll make this less of a wild goose chase?

My phone details:

```
Model: Nexus 5X
Android version: 7.1.2
Baseband version: M8994F-2.6.37.2.21
Kernel version: 3.10.73-ge570678
Build version: N2G47F

```

Thanks in advance for any help or insight.

Answer: 
If you want to install without modifying `/system` then it's impossible. **So the answer is "No, you can't" with neither root access nor recovery flashing.** But if you simply wany to DIY without using a custom recovery, it's OK.  

Takine [OpenGApps](https://opengapps.org) as example. Download their ZIP and extract it. 

1. Install BusyBox
2. Use `busybox lunzip` to extract the `.tar.lz` files in `Core/`
3. Move files other than APKs to `/system`. You will find things to be merges into `etc/` and `framework/`. Take care of file mode (permissions) and owner/group.
4. Install `GoogleServicesFramework.apk` **as system app**. In my experiments it sometimes fail if not installed as system app.
5. Install the rest of the APKs as normal.

You can't install GApps without modifying `/system`. As you see, there are quite a few configuration files that will be merged into `/system/etc` during installation, and a few *essential* framework JARs to be installed to `'/system/framework`. They won't work if installed elsewhere.
Google for play services framework and play store APKs (hosted third party) (I believe running the play store will install/update the framework, so that might be the only one you need), then install the rest of them from the play store. If you're rooted, titanium backup can try to convert some of them to system apps.