ashsimpl.exe caused an invalid page fault in @oooo:1b10f3dd
This happens when I want start scanning using 4.5
I can move the error message window and complete the scanninig process.
What is the error message all about???
What OS?
What version of Avast?
Any errors in Avast’s log file?
Any errors in the event or system logs?
Have you tried a repair?
etc etc.
The problem is related to Microsoft Jet Drivers.
To get rid of the error, either update the drivers (you can download them as MDAC package from Microsoft), or switch the avast! database type from ODBC to XML (e.g. by changing the line Database=ODBC to Database=XML in avast4.ini file).
Which is better ODBC or XML?
sorry this is offtopic, i’d like to know 
For the Home version, they are “equal”.
For the Professional version of avast!, XML is missing some functionality (compared to ODBC).