Edited by <!profile=WyllyWylly>WyllyWylly<!/profile> to add a link to the original post and for the MSKB article.

Many will be familiar with my problem of not being able to access shared folders on one of my machines, I have finally solved the problem after spending two days on the web searching every available clue. The solution is contained in the <!mskb=177078>Microsoft Knowledge Base Article 177078<!/mskb>. I guess the problem lies with Symantec (Norton) Anti-Virus but I found reference to other programs that could cause the problem (Acronis for one).

I tried the IRPStackSize in accordance with the KB article but it was only when I pushed the envelope that I achieved success.

The problem was on the computer I could not access, not the computer from where I was getting the problem, that had me on the wrong path.

My thanks go to all who helped me, I am at a loss as to what to worry about now.