We had to change the name of a table. All the existing queries were obviously still pointing to the old table name. For each query, I opened it in SQL view, cut the code and pasted it into Word to use Word's "replace" feature to change all references to that old table name to the new table name. I then pasted the code back into the query's SQL view.
Then I noticed something odd; I opened those queries in Design View and in the "Field" row, each column had a sequential prefix ("Expr1:" "Expr2:" "Expr3:", etc.). I deleted the prefixes and everything works fine. But does anyone know why those prefixes appeared?