1. Hangouts doesn’t work in Internet Explorer from the Windows 8 Start screen:
If you are using Windows 8 and trying to launch Internet Explorer from its Start screen, then you will notice that Hangouts doesn't work. It happens because Hangouts requires a plug-in to operate on Internet Explorer and plug-ins are not allowed on full-screen version of IE. If you face this problem you have two choices. You can run IE in desktop mode instead of running it from the Start screen and then install Hangouts. Or just opt for another Hangouts-supporting browser.
2. Hangouts causes alert overload on multiple devices simultaneously:
If Hangouts is logged in on both your desktop and smartphone at the same time, notifications arrive in both devices. It's an annoying issue with Hangouts. While some users find it disturbing, others handle it in a different way. To avoid this annoyance, there are some solutions too. You can sign out of Hangouts on any of the devices which you are not using presently. Android devices have some more options too. Go to Menu>>Snooze notifications and suspend alerts on the device. You can suspend notifications for an indefinite time by selecting the gear icon in the Hangout window and unchecking the Notifications box.
3. Portrait mode photos automatically turn into landscape mode:
This issue has been found on select Android phones when pictures are sent through MMS. If you clear application data from the Android Applications Manager it might help at least for some time. You should not use the camera within Hangouts to click pictures. Do take pictures separately by the standard Android camera.
4. Complicated video-calling:
In the Chrome browser it's not required to have a plug-in for Hangouts to work if Google Apps is not being uses which means you have to install Hangouts plug-in to make video calls. You can also install the Hangouts Chrome app by adding Hangouts to the Chrome App Launcher and initiate a new video call. Hangouts has also a list of supported webcams, which means every webcam, microphone and audio devices are not supported by Hangouts. You should make sure you have selected the correct audio gear within Hangout's settings menu. Initiate a new video call and click on the gear icon. If there is a video-related problem, you can also restart your browser or computer to resolve the issue.
5. Problem with Hangouts Browser plug-in:
If you are running 64-bit Internet Explorer then the Hangouts plug-in is not supported at all. If you are using Chrome, the check Chrome://plugins/ to see if the Google Talk plug-in is already installed and enabled or not. Well, Hangouts app is different from Hangouts plug-in. In case the Hangouts app gets uninstalled, you can always download it again from the Chrome web store.