the table is most likely locked. Try this trick to retrieve dirty data
SELECT TOP 100 * FROM XXX (NOLOCK)
Read about the query hints
here[
^]
You can experiment with FAST hint that allows to select fast first n rows:
Quote:
FAST number_rows
Specifies that the query is optimized for fast retrieval of the first number_rows. This is a nonnegative integer. After the first number_rows are returned, the query continues execution and produces its full result set.