diff --git a/src/main.rs b/src/main.rs
index 80e380fe9..cf4219760 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -147,20 +147,28 @@ fn set_working_dir(opts: &Opts) -> Result<()> {
 
 /// Detect if the user accidentally supplied a path instead of a search pattern
 fn ensure_search_pattern_is_not_a_path(opts: &Opts) -> Result<()> {
-    if !opts.full_path
-        && opts.pattern.contains(std::path::MAIN_SEPARATOR)
-        && Path::new(&opts.pattern).is_dir()
-    {
-        Err(anyhow!(
+    if !opts.full_path && opts.pattern.contains(std::path::MAIN_SEPARATOR) {
+        let is_dir = Path::new(&opts.pattern).is_dir();
+        let mut message = format!(
             "The search pattern '{pattern}' contains a path-separation character ('{sep}') \
-             and will not lead to any search results.\n\n\
-             If you want to search for all files inside the '{pattern}' directory, use a match-all pattern:\n\n  \
-             fd . '{pattern}'\n\n\
-             Instead, if you want your pattern to match the full file path, use:\n\n  \
-             fd --full-path '{pattern}'",
+             and will not lead to any search results.\n\n",
             pattern = &opts.pattern,
             sep = std::path::MAIN_SEPARATOR,
-        ))
+        );
+        if is_dir {
+            message += &format!(
+                "If you want to search for all files inside the '{pattern}' directory, \
+                 use a match-all pattern:\n\n  \
+                 fd . '{pattern}'\n\n",
+                pattern = &opts.pattern,
+            );
+        }
+        message += &format!(
+            "If you want your pattern to match the full file path, use:\n\n  \
+             fd --full-path '{pattern}'",
+            pattern = &opts.pattern,
+        );
+        Err(anyhow!(message))
     } else {
         Ok(())
     }
diff --git a/tests/tests.rs b/tests/tests.rs
index c125d3a59..664110de3 100644
--- a/tests/tests.rs
+++ b/tests/tests.rs
@@ -374,6 +374,32 @@ fn test_multi_file_with_missing() {
     );
 }
 
+/// Pattern containing path separator should always produce an error,
+/// not only when the pattern is an existing directory.
+/// Regression test for https://github.com/sharkdp/fd/issues/1873
+#[test]
+fn test_path_separator_in_pattern_non_directory() {
+    let te = TestEnv::new(DEFAULT_DIRS, DEFAULT_FILES);
+
+    // A pattern with '/' that is NOT an existing directory should still error
+    te.assert_failure_with_error(
+        &["foo/bar"],
+        "[fd error]: The search pattern 'foo/bar' contains a path-separation character ('/') and will not lead to any search results.",
+    );
+}
+
+#[test]
+fn test_path_separator_in_pattern_existing_directory() {
+    let te = TestEnv::new(DEFAULT_DIRS, DEFAULT_FILES);
+
+    // A pattern with '/' that IS an existing directory should also error
+    // and include the directory-specific hint
+    te.assert_failure_with_error(
+        &["one/two"],
+        "[fd error]: The search pattern 'one/two' contains a path-separation character ('/') and will not lead to any search results.",
+    );
+}
+
 /// Explicit root path
 #[test]
 fn test_explicit_root_path() {