You want to make an export of thousends of files.
When you see thismessage : "No instance available"
When you see the message "No instance available", this tells you that the amount of files is to high to for the export
You use the Lastname to create a smaller list by splitting the export ( not more then 2000 records).
How to do this
Make a Selection Candidates/Contacts;
Add to the search rule
Lastname | starts with | a b c
The list of recors will be smallen now, send the e-mail or export the records.
Repeat this for :
Lastname | Starts with | d e f g h i
The exact number of files you can export with the export action is not to say on forehand.
2000 is guideline, i some cases the system is able to handle a bit more, in some cases less, depends on how many data must be retrieved