I have a VF page (called prodinfo ). 

On Sandbox

- Accessing as regular VF page (URL looks like http://xxxxx/apex/prodinfo)

- - - HTML version output - works fine

- - - PDF version output (by just adding 'renderas="pdf" in the page tag) - works fine

- Accessing as Sites page (after setting up a site to refer to this page. URL looks like http://xxxxx.force.com/prodinfo)

- - - HTML version output works fine

- - - PDF version output (by just adding 'renderas="pdf" in the page tag) - works fine

On Production

- Accessing as regular VF page (URL looks like http://yyyyy/apex/prodinfo)

- - - HTML version output - works fine

- - - PDF version output (just by adding 'renderas="pdf" in the page tag) - works fine

- Accessing as Sites page (after setting up a site to refer to this page. URL looks like http://yyyyy.force.com/prodinfo)

- - - HTML version output (regular page tags etc.) works fine

- - - PDF version output (just by adding 'renderas="pdf" in the page tag) - FAILS with the dreaded InMaintenance error.

There is not change to code other than to add and remove the renderas clause.

As soon as I remove the renderas="pdf" part on the page, the VF page on production accessed as a Sites page shows up fine.

Any help / information / pointers greatly appreciated.

Thanks

SC