Here is the list of Disadvantages of Appium:
Script execution on multiple iOS simulators: Appium accelerates iOS app testing by allowing to use simulators. The simulators make it easier for testers to mimic internal behaviour of the underlying iOS devices. But it does not allow users to run multiple test scripts on multiple simulators at a time.
Setup for iOS: Setting your framework for iOS is really tough, you will not find good documentation and due to security reasons setting up on real device is quite complex.
No support for Android Alert Handling: At present, Appium does not support Android alert handling directly. Hence, the users lack the option to evaluate alert handling through native APIs. They have to handle alerts in a different way to produce accurate test results.
Image and Font Recognition: Many testers nowadays opt for tools with image recognition capability to evaluate mobile apps and games more precisely. Unlike other widely used mobile app testing tools, Appium lacks the capability to locate images automatically. The testers have to work with screen coordinates additionally to make Appium locate and recognize images. Issue with recognizing font types and sizes
Mobile Gesture Support: Few gestures support are not implemented yet, like double-clicking for Java Library. The testing professionals have to put extra time and effort to test these gestures.
Limited support for Android Old Versions: At present, Appium does not support earlier versions of Android. It supports only Android 4.2 and later. Likewise, it also does not support older APIs for Android. The developers have to integrate Appium with Selenium to test APIs lower than version 16. There are still a large number of devices that run on Android 4.1 Lollypop. Hence, developers find it difficult to test mobile apps developed by targeting different versions of Android.
Working With App Objects Is Difficult: Working with app objects for both iOS and Android isn’t easy, and falls into the top testing challenges coming from practitioners.
The Appium framework relies on iOS XCUITest and Espresso Android (UI automation framework). This means that users needs to be familiar with the object structure. And they need to know how to use the Appium object spy correctly.
Documentation: Less documentation and tutorials.
Hybrid App Support: Appium has limited support for hybrid app testing. You will not be able to test the action that allows switching of applications from native to web app and from web app to native.
Windows Application Support: Not a good support for Windows. Windows Application Driver (WinAppDriver) is a service to support Selenium-like UI Test Automation on Windows Applications but still there are lots of challenges.
Toast Message: A toast is a non-modal dialog that appears and disappears in the span of a few seconds. It may also optionally have a small close "X". Typically, toast messages display one or two-line non-critical messages that do not require user interaction. There is no direct support for toast messages.
Slow Test Execution: Tests can be slow due to the remote webdriver dependency, network issues, and processing commands.
Test Framework Stability: Stability issues can occur when executing through CI or at scale and in parallel.