diff --git a/copyparty/ftpd.py b/copyparty/ftpd.py
index fd5d0349..949a7457 100644
--- a/copyparty/ftpd.py
+++ b/copyparty/ftpd.py
@@ -174,7 +174,7 @@ class FtpFs(AbstractedFS):
                 t = "Unsupported characters in [{}]"
                 raise FSE(t.format(vpath), 1)
 
-            fn = sanitize_fn(fn or "", "")
+            fn = sanitize_fn(fn or "")
             vpath = vjoin(rd, fn)
             vfs, rem = self.hub.asrv.vfs.get(vpath, self.uname, r, w, m, d)
             if (
diff --git a/copyparty/httpcli.py b/copyparty/httpcli.py
index ee0a4e94..966dd87b 100644
--- a/copyparty/httpcli.py
+++ b/copyparty/httpcli.py
@@ -2419,7 +2419,7 @@ class HttpCli(object):
             if rnd:
                 fn = rand_name(fdir, fn, rnd)
 
-            fn = sanitize_fn(fn or "", "")
+            fn = sanitize_fn(fn or "")
 
         path = os.path.join(fdir, fn)
 
@@ -2857,7 +2857,7 @@ class HttpCli(object):
             name = name.translate(tl)
         dbv, vrem = vfs.get_dbv(rem)
 
-        name = sanitize_fn(name, "")
+        name = sanitize_fn(name)
         if (
             not self.can_read
             and self.can_write
@@ -3353,7 +3353,7 @@ class HttpCli(object):
         if "nosub" in vfs.flags:
             raise Pebkac(403, "mkdir is forbidden below this folder")
 
-        rem = sanitize_vpath(rem, "/")
+        rem = sanitize_vpath(rem)
         fn = vfs.canonical(rem)
 
         if not nullwrite:
@@ -3397,7 +3397,7 @@ class HttpCli(object):
             t = "you can only create .md files because you don't have the delete-permission"
             raise Pebkac(400, t)
 
-        sanitized = sanitize_fn(new_file, "")
+        sanitized = sanitize_fn(new_file)
         fdir = vfs.canonical(rem)
         fn = os.path.join(fdir, sanitized)
 
@@ -3549,7 +3549,7 @@ class HttpCli(object):
                     # fallthrough
 
                 fdir = fdir_base
-                fname = sanitize_fn(p_file or "", "")
+                fname = sanitize_fn(p_file or "")
                 abspath = os.path.join(fdir, fname)
                 suffix = "-%.6f-%s" % (time.time(), dip)
                 if p_file and not nullwrite:
diff --git a/copyparty/szip.py b/copyparty/szip.py
index 91fa2a34..12caf91f 100644
--- a/copyparty/szip.py
+++ b/copyparty/szip.py
@@ -8,7 +8,7 @@ import time
 from .authsrv import AuthSrv
 from .bos import bos
 from .sutil import StreamArc, errdesc
-from .util import min_ex, sanitize_fn, spack, sunpack, yieldfile, zlib
+from .util import VPTL_WIN, min_ex, sanitize_to, spack, sunpack, yieldfile, zlib
 
 if True:  # pylint: disable=using-constant-test
     from typing import Any, Generator, Optional
@@ -104,7 +104,7 @@ def gen_hdr(
     ret += spack(b"<LL", vsz, vsz)
 
     # windows support (the "?" replace below too)
-    fn = sanitize_fn(fn, "/")
+    fn = sanitize_to(fn, VPTL_WIN)
     bfn = fn.encode("utf-8" if utf8 else "cp437", "replace").replace(b"?", b"_")
 
     # add ntfs (0x24) and/or unix (0x10) extrafields for utc, add z64 if requested
diff --git a/copyparty/up2k.py b/copyparty/up2k.py
index edcae7eb..f919befe 100644
--- a/copyparty/up2k.py
+++ b/copyparty/up2k.py
@@ -3323,7 +3323,7 @@ class Up2k(object):
                                     job["ptop"] = vfs.realpath
                                     job["vtop"] = vfs.vpath
                                     job["prel"] = rem
-                                    job["name"] = sanitize_fn(job["name"], "")
+                                    job["name"] = sanitize_fn(job["name"])
                                     ud2 = (vfs.vpath, job["prel"], job["name"])
                                     if ud1 != ud2:
                                         # print(json.dumps(job, sort_keys=True, indent=4))
@@ -5186,7 +5186,7 @@ class Up2k(object):
                     job["ptop"] = vfs.realpath
                     job["vtop"] = vfs.vpath
                     job["prel"] = rem
-                    job["name"] = sanitize_fn(job["name"], "")
+                    job["name"] = sanitize_fn(job["name"])
                     ud2 = (vfs.vpath, job["prel"], job["name"])
                     if ud1 != ud2:
                         self.log("xbu reloc2:%d..." % (depth,), 6)
diff --git a/copyparty/util.py b/copyparty/util.py
index 3544d219..0bbb935a 100644
--- a/copyparty/util.py
+++ b/copyparty/util.py
@@ -2245,28 +2245,30 @@ def undot(path: str) -> str:
     return "/".join(ret)
 
 
-def sanitize_fn(fn: str, ok: str) -> str:
-    if "/" not in ok:
-        fn = fn.replace("\\", "/").split("/")[-1]
-
+def sanitize_fn(fn: str) -> str:
+    fn = fn.replace("\\", "/").split("/")[-1]
     if APTL_OS:
-        fn = fn.translate(APTL_OS)
-        if ANYWIN:
-            bad = ["con", "prn", "aux", "nul"]
-            for n in range(1, 10):
-                bad += ("com%s lpt%s" % (n, n)).split(" ")
-
-            if fn.lower().split(".")[0] in bad:
-                fn = "_" + fn
-
+        fn = sanitize_to(fn, APTL_OS)
     return fn.strip()
 
 
-def sanitize_vpath(vp: str, ok: str) -> str:
+def sanitize_to(fn: str, tl: dict[int, int]) -> str:
+    fn = fn.translate(tl)
+    if ANYWIN:
+        bad = ["con", "prn", "aux", "nul"]
+        for n in range(1, 10):
+            bad += ("com%s lpt%s" % (n, n)).split(" ")
+
+        if fn.lower().split(".")[0] in bad:
+            fn = "_" + fn
+    return fn
+
+
+def sanitize_vpath(vp: str) -> str:
     if not FNTL_OS:
         return vp
     parts = vp.replace(os.sep, "/").split("/")
-    ret = [sanitize_fn(x, ok) for x in parts]
+    ret = [sanitize_to(x, APTL_OS) for x in parts]
     return "/".join(ret)