How to Fix WhatsApp Crashing on iPhone 18 (Post-Update Crash Loop)
When WhatsApp closes a few seconds after launch, start with the app and device checks that do not remove chat data. A crash after an update does not by itself prove that the update caused it, so work through updates, connection, and storage before deleting the app.
First restart the iPhone, check for an iOS update, and install any available WhatsApp update. Then confirm you have a working internet connection and enough free iPhone storage. You can review storage at Settings > General > iPhone Storage.
Protect your chat history before reinstalling
If WhatsApp stays open long enough, check whether you have an iCloud chat backup: open WhatsApp, then go to Settings > Chats > Chat Backup. Note the date and size of the latest backup before changing anything. A restore cannot bring back messages sent or received after that backup.
After confirming a backup exists, uninstall and reinstall WhatsApp. Verify the same phone number and Apple ID when prompted, then select Restore Chat History. The iPhone and iCloud account both need enough available storage for the restore.
When the app will not stay open
Do not delete WhatsApp just to test whether reinstalling helps if you cannot confirm a usable backup. First free space if needed and retry after restarting the phone. If a reinstall is the next step, understand that it removes the app; restore is only available when the required iCloud backup and matching phone number are available.
Note:
A crash that affects every part of WhatsApp is different from a crash triggered by one particular chat. Test another chat after the app opens; use the chat-specific path only when the rest of the app remains usable.
For a WhatsApp-specific computer backup before taking a more disruptive troubleshooting step, Dr.Fone - WhatsApp Transfer provides a dedicated WhatsApp backup workflow.
