I don't know of a way to switch it off (Print Preview does tend to execute
merge fields) but you could consider avoiding it by using a different type
of field. For example, if you set up a custom document property (in
File|Properties) for each item you currently have as an ASK, all you really
need to do is
a. go into File|Properties|Custom and modify the value of each property
b. use { DOCPROPERTY "the property name" } fields instead of { REF } fields
wherever you need the results.

Peter Jamieson