Solutions to possible problems

I can't install the app

Correction 1: If you already have a Google Camera app installed, try removing it before installing a new one. If your ROM comes with a pre-installed Gcam, remove it (for example: using Titanium Backup + root) or use a different ROM.
Correction 2: The version you are trying to install is not compatible with your version of Android. Use a different apk.

Correction 1: You may need to install a front camera patch or activate an option to correct the problem.
Correction 2: The version of GCam you are using is not fully compatible with your phone or ROM. Try a different version.

Correction 1: Photos on the go don't work on Android 7.x, only Android 8.x or later.
Correction 2: This feature requires Google Photos. Other apps in the gallery will display still images.
Correction 3: Motion pictures require specific settings to work. Sometimes you need to use a Pixel setting and 16: 9 resolution instead of the 4: 3 default. Sometimes there is a menu where you can choose the resolution for this feature (try them all).

Correction 1: You may need to install a front camera patch or activate an option to correct the problem.
Correction 2: Older versions may not work on newer versions of Android (and vice versa). Try an older apk if you are using an outdated version of Android or a newer apk if you are using The latest version of Android.
Correction 3: Google's camera will crash if it has not submitted a GApps package. Read "How to use GCam without GApps" for more information.
Correction 4:If this happens after you upgrade to a new version or after changing application settings, there is a chance of not using compatible settings. Clear app data or uninstall and reinstall the app again.
Correction 5: Using a root file manager / explorer, delete the following files (ignore the ones you can't find) and try again:
/system/etc/permissions/com.google.android.camera.experimental2017.xml
/system/etc/permissions/com.google.android.camera.experimental2016.xml
/system/framework/com.google.android.camera.experimental2016.jar
/system/framework/com.google.android.camera.experimental2017.jar

In some cases, you also need to redo an updated GApps package after removing the files. Keep in mind that intermittent and dirty GApps can cause some problems if the GApps you already installed are old. A nandroid backup (TWRP) or a clean install is recommended.
Correction 6: Google Camera runs only on ROMs with Camera2 API enabled and some ROMs do not enable it. (learn how to enable)

There is a good chance that you will use the wrong settings and cause the app to crash.

Correction 1: Go to "Debugging and Tools", uncheck "camera.use_photos" and restart the application.
Correction 2: Install the app Google Fotos and try again.

There are 3 HDR options in most versions of Gcam: HDR Off, HDR + On, and Enhanced HDR + (HDR Off, HDR + Auto, and HDR + Enabled on older versions): Try using enhanced HDR +. Although it is slower, take better pictures in tough conditions

Only works on some phones. Most versions of GCam based on 5.x do not support, but some based on 6.x may work. Make sure you select the correct FPS for your phone (e.g. 120 instead of 240), Explore the settings menu to see if this option is available.
Note about Android 7.x: Older versions of Google Camera supported slow motion on many Android 7 ROMs, but some phones needed an updated media_profiles.xml file with high speed profiles. Try to find in XDA for your phone, maybe other users with the same phone have a solution to this problem.

Correction 1: Change one of the settings (for example, turn off camera sounds), restart the app, and try again.
Correction 2: Reinstall the application (remove and reinstall). Sometimes configurations of older versions cause problems.