****Attempt to repair install of MSXML 4.0******If this does not resolve it try:- Upgrade MSXML 4.0 to Service Pack 3 (Repair if already upgraded)- Clear out the offending default.gdb files- Create a new default.gdb within the user home using ArcCatalogWalkthrough Process1. Download and install SP3 for MSXML 4.0 (Provided by Microsoft)1. Clear out all default.gdb files within <user home>\My Documents\ArcGIS2. Open ArcCatalog3. Within ArcCatalog, connect to Folder (<user home>\My Documents\ArcGIS)4. Within ArcCatalog right-click > <user home>\My Documents\ArcGIS > New > File Geodatabase5. Name the new File Geodatabase as "Default.gdb"6.A system restore to an earlier date.This would be in case if ArcMap was working fine and then stopped working.