Windows Error Reporting
Saturday, December 06th, 2008 | Author:

C:\DOCUME~1\USER~1\LOCALS~1\Temp\WER8bd7.dir00\w3wp.exe.mdmp

C:\DOCUME~1\USER~1\LOCALS~1\Temp\WER8bd7.dir00\appcompat.txt

Above error pop ups when Error Reporting is enabled on your system and w3wp.exe faces an error.
Windows Error Reporting increases Hard Disk space , by adding above pop ups in two different dump files i.e. HDMP and MDMP
HDMP (Heap Dump) – Uncompressed error dump file generated by Windows when a program has an error or crashes.
MDMP (Mini Dump) – Compressed Heap Dump files are saved as Mini dump (MDMP) files and may be sent to Microsoft as part of an error reporting process.

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