> Did you build the index on the same machine?  Are you indexing very
> large documents and using store description?

Yes, the index was build on the same machine. I tried several sources
(websites, filesystem) and curretly the files are max 50 kb. 
I tried to enable or disable StoreDescription, PropCompressionLevel
in the configuration file. Always with the same result.

> For swish to read an incorrect value back would mean that either the
> property file was corrupt or that swish somehow got confused when
> indexing into the prop file to fetch the compressed property.

Is there a way to find out if the index wasn`t created properly?
(This would reduce the problem to searching)