Notes about the 4DA file extension:
To open this file type, a required software must be installed. Without it you only see a Windows message "The following file cannot be opened
" (Windows 7) or "How do you want to open this file?
" (Windows 10) if you double-click the file. There click on "More apps"
and choose a suitable software to view such files on your PC or from email attachments.
The 4DA file type is primarily associated with '4th Dimension User Form' by 4D, Inc. File extension 4da has got to do with storing and managing user forms in 4th Dimension. User forms are stored in a separate file with a .4DA extension, placed next to the main structure file (.4DB/.4DC). The behavior of this file is transparent.
Detailed information for file extension 4DA:
File classification: Database
To change file associations press Windows Key
and then Apps and Features
> Default apps
> Choose default apps by file type
Invalid file associations could be the result of underlying issues within your Windows PC.