This procedure explains how to clear the cache of the Dropbox app on your Android smartphone. This operation is necessary in situations where you want to permanently delete a file from Dropbox (as a copy of file is kept in the cache) or to fix sync issues that you may encounter with the app.
Open the Dropbox app. Tap on the Menu key (3 vertical dots) > Settings:
Scroll to the Advanced Features section and tap on Clear Cache: