diff --git a/Sources/System/FilePath/FilePathWindows.swift b/Sources/System/FilePath/FilePathWindows.swift
index d8927959..fa079b1b 100644
--- a/Sources/System/FilePath/FilePathWindows.swift
+++ b/Sources/System/FilePath/FilePathWindows.swift
@@ -85,10 +85,10 @@ struct _Lexer {
     slice._eat(.backslash) != nil
   }
 
-  // Try to consume a drive letter and subsequent `:`.
+  // Try to consume a drive designator and subsequent `:`.
   mutating func eatDrive() -> SystemChar? {
     let copy = slice
-    if let d = slice._eat(if: { $0.isLetter }), slice._eat(.colon) != nil {
+    if let d = slice._eat(if: { !isSeparator($0) && $0 != .colon }), slice._eat(.colon) != nil {
       return d
     }
     // Restore slice
diff --git a/Tests/SystemTests/FilePathTests/FilePathSyntaxTest.swift b/Tests/SystemTests/FilePathTests/FilePathSyntaxTest.swift
index 0fdfbc27..ebb04f58 100644
--- a/Tests/SystemTests/FilePathTests/FilePathSyntaxTest.swift
+++ b/Tests/SystemTests/FilePathTests/FilePathSyntaxTest.swift
@@ -595,7 +595,7 @@ final class FilePathSyntaxTest: XCTestCase {
       ),
     ]
 
-    let windowsPaths: Array<SyntaxTestCase> = [
+    var windowsPaths: Array<SyntaxTestCase> = [
       .windows(#""#, absolute: false,  components: []),
 
       .windows(
@@ -628,6 +628,15 @@ final class FilePathSyntaxTest: XCTestCase {
         components: ["foo", "bar.exe"]
       ),
 
+      .windows(
+        #"+:\foo"#,
+        absolute: true,
+        root: #"+:\"#, relative: #"foo"#,
+        dirname: #"+:\"#, basename: "foo",
+        stem: "foo",
+        components: ["foo"]
+      ),
+
       .windows(
         #"C:foo\bar"#,
         absolute: false,
@@ -769,6 +778,19 @@ final class FilePathSyntaxTest: XCTestCase {
       // TODO: partially-formed Windows roots, we should fully form them...
     ]
 
+#if os(Windows)
+    windowsPaths.append(
+      .windows(
+        #"€:\foo"#,
+        absolute: true,
+        root: #"€:\"#, relative: #"foo"#,
+        dirname: #"€:\"#, basename: "foo",
+        stem: "foo",
+        components: ["foo"]
+      )
+    )
+#endif
+
     for test in unixPaths {
       test.runAllTests()
     }