If your device is rooted, troubleshoot this issue by following the steps below:
1. Using a root file manager, go to /data/data.
2. Find the WeChat package: com.tencent.mm.
3. Delete all the files within that folder.
4. Restart your device.
5. Install WeChat again to check whether it works or not.
If your device is not rooted, try the following method:
1. Go to Settings > Application Manager > All
2. Find Google Play Store, tap the Clear Data and Clear Cache buttons.
3. Find Download Manager, tap the Clear Data and Clear Cache buttons.
4. Go to Settings > Account > remove Google Account
5. Restart your device
6. Add Google account again
7. Install WeChat again
