How should I recover the PDF files in WhatsApp, that were not downloaded?

 recover the PDF files in WhatsApp, that were not downloaded:

• Uninstall and reinstall the WhatsApp application. When WhatsApp is finished installing, you'll be given the choice to Restore your Google Drive media and conversation information.
• A Backup Found section will display the date and size of the most recent backup. The restoration process will begin once you pick Restore. Its length is determined by the amount of data you have backed up.
• When the process is complete, WhatsApp will notify you of the number of messages that have been restored. Simply click Next, provide your name in the name window, and your previously saved chats will be accessible. Wait a few minutes longer, and the backed-up media (including PDF files) will start to appear.
• By default, media sent over WhatsApp is configured to download, but this can be changed in the WhatsApp settings. To do so on an Android smartphone, go to WhatsApp settings and select the Data Usage section, which will bring you a new set of options, including the Media Auto-Download option. To prevent WhatsApp from automatically saving your material to your smartphone, simply uncheck all of the options.

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