I can't replicate your results.
Using FileMaker15, I created a small test file with a field of type text
Created 4 records entering the text
I then created and performed two scripts. The first is exactly like what you report, using =Building A as its stored criteria (Though in actual practice, I never use stored criteria. I used it here to keep the test exactly like yours.*) In the second, I used =Building C as my criteria.
The first script found exactly 1 record, Building A as expected. The Second record found Building C and Building CC. Might the second example more closely match the results that you are getting?
If so, the solution is to use ==Building C so that this is an exact match rather than a "starts with" match.
*I normally use find scripts in this format:
Enter Find mode--no pause option selected
Set Field [Table::Field ; "==Building C"]
Set Error Capture [on]
#Handle what happens when no records are found
If [Get ( FoundCount ) = 0 ]
I suspect that the examples you give are misleading, and the true data would match Phil's speculation. If so, it is another example of why it is usually better to give real-life descriptions and not abstract concepts.
Actually this is real-life data. Changing the operator in the Find from = to == makes it work correctly. Thank you for your help.
Yet something is different in your DB from what you report or I would not be getting different results.
Phil tested your steps as described, and couldn't replicate your result. His results are exactly as we would have expected. And adding '==' is exactly the solution to stop a 'Building CC' record being found with a 'Building C' record.
In other words it looks like something else is going on, which may come back to surprise you later.
Search for (no quote marks):
'building a' will return records with 'building a', 'building a2', 'building abcdef123' and 'a building'
'build a' will return records with 'building a', 'building a2', 'building abcdef123' and 'a building'
'a build ' will return records with 'building a', 'building a2', 'building abcdef123' and 'a building'
'ab build' will return records with 'building abcdef123'
'=ab build' will return records with 'building ab' and 'ab building'