WER file format contains information about Windows application and service errors, and crashes generated by Windows Error Reporting service. WER service is a part of Microsoft Winqual tool package which enables software developers to monitor and address any reported quality issues with their software.

WER files store information and data regarding application crashes and enable to send them to Microsoft or software/device producer/vendor as a part of error reporting system. Microsoft Winqual services can be accessed or disabled/enabled via a web browser. WER raport files are stored in applications system folder.