Unknown argument for ':' operator. Complete Regular Expression required in search string.

This error generally occurs during search or replace when regular expressions or wildcards are used in a search string. The operator colon (:) was entered but the argument that followed was not a valid argument.


Arguments for the colon (:) operator are case-sensitive.

To correct this error

  1. Review the correct regular expression syntax located in the topic "Regular Expressions."

  2. Double-check that the correct case of the argument was used.

  3. If you are using an Input Method Editor (IME), make sure that the argument is not given using full-width characters.

See Also


Regular Expressions (Visual Studio)

Quick Find, Find and Replace Window

Find in Files, Find and Replace Window