Date Format keeps changing itself

I'll share some steps you can take to resolve this issue with QuickBooks Online (QBO) date format, @Emlyn.

You can check the date format on the Account and Settings page. Here's how:

1. Go to the Gear icon, then select Account and settings.
2. Click the Advanced tab.
3. Look for the Other preferences section, then tap the Date format drop-down menu.
4. Change it to the format you want to use. 
5. Hit Save, then Done.

If the date format is already correct or if you continue to have the same issue, I suggest opening your browser's private window. It isolates cache, which is the common cause of unusual behaviors in browsers. 

• Google Chrome: Ctrl + Shift + N
• Microsoft Edge: Ctrl + Shift + P
• Firefox: Ctrl + Shift + P
• Safari: Command + Shift + N

If that works, go back to your regular browser and clear its cache. Otherwise, open an alternative browser that's available for you. 

Post a reply if you have other questions about date formats in QBO. I'll be sure to get back to you. Have a great day!