diff --git a/gvsbuild/utils/builder.py b/gvsbuild/utils/builder.py
index 9b12340f0..3d07882a1 100644
--- a/gvsbuild/utils/builder.py
+++ b/gvsbuild/utils/builder.py
@@ -32,7 +32,6 @@
 from typing import Optional
 from urllib.error import ContentTooShortError, URLError
 from urllib.request import urlopen
-from string import ascii_uppercase
 
 from .base_expanders import dirlist2set, make_zip
 from .base_project import Project
@@ -231,10 +230,21 @@ def __check_tools(self, opts):
         log.start("Checking msys tool")
         msys_path = opts.msys_dir
         if not msys_path or not Path.exists(msys_path):
-            # list of drive letters to check
-            possible_drives = ['%s:' % d for d in ascii_uppercase if os.path.exists('%s:' % d)]
-            possible_paths = [r"\msys64", r"\tools\msys64", r"\msys32", r"\tools\msys32"]
-            all_possible_paths = [Path(drive + path) for drive in possible_drives for path in possible_paths]
+            drive_letters = ("C:", "D:", "E:", "F:")
+            possible_drives = [
+                drive for drive in drive_letters if os.path.exists(drive)
+            ]
+            possible_paths = [
+                r"\msys64",
+                r"\tools\msys64",
+                r"\msys32",
+                r"\tools\msys32",
+            ]
+            all_possible_paths = [
+                Path(drive + path)
+                for drive in possible_drives
+                for path in possible_paths
+            ]
 
             for path in all_possible_paths:
                 if Path.exists(path):