diff --git a/copyparty/bos/bos.py b/copyparty/bos/bos.py
index 6c876e04..408244b9 100644
--- a/copyparty/bos/bos.py
+++ b/copyparty/bos/bos.py
@@ -2,18 +2,22 @@
 from __future__ import print_function, unicode_literals
 
 import os
+import time
 
 from ..util import SYMTIME, fsdec, fsenc
 from . import path as path
 
 if True:  # pylint: disable=using-constant-test
-    from typing import Any, Optional
+    from typing import Any, Optional, Union
+
+    from ..util import NamedLogger
 
 MKD_755 = {"chmod_d": 0o755}
 MKD_700 = {"chmod_d": 0o700}
+UTIME_CLAMPS = ((max, -2147483647), (max, 1), (min, 4294967294), (min, 2147483646))
 
-_ = (path, MKD_755, MKD_700)
-__all__ = ["path", "MKD_755", "MKD_700"]
+_ = (path, MKD_755, MKD_700, UTIME_CLAMPS)
+__all__ = ["path", "MKD_755", "MKD_700", "UTIME_CLAMPS"]
 
 # grep -hRiE '(^|[^a-zA-Z_\.-])os\.' . | gsed -r 's/ /\n/g;s/\(/(\n/g' | grep -hRiE '(^|[^a-zA-Z_\.-])os\.' | sort | uniq -c
 # printf 'os\.(%s)' "$(grep ^def bos/__init__.py | gsed -r 's/^def //;s/\(.*//' | tr '\n' '|' | gsed -r 's/.$//')"
@@ -99,6 +103,40 @@ def utime(
         return os.utime(fsenc(p), times)
 
 
+def utime_c(
+    log: Union["NamedLogger", Any], p: str, ts: int, follow_symlinks: bool = True, throw: bool = False
+) -> Optional[int]:
+    clamp = 0
+    ov = ts
+    bp = fsenc(p)
+    now = int(time.time())
+    while True:
+        try:
+            if SYMTIME:
+                os.utime(bp, (now, ts), follow_symlinks=follow_symlinks)
+            else:
+                os.utime(bp, (now, ts))
+            if clamp:
+                t = "filesystem rejected utime(%r); clamped %s to %s"
+                log(t % (p, ov, ts))
+            return ts
+        except Exception as ex:
+            pv = ts
+            while clamp < len(UTIME_CLAMPS):
+                fun, cv = UTIME_CLAMPS[clamp]
+                ts = fun(ts, cv)
+                clamp += 1
+                if ts != pv:
+                    break
+            if clamp >= len(UTIME_CLAMPS):
+                if throw:
+                    raise
+                else:
+                    t = "could not utime(%r) to %s; %s, %r"
+                    log(t % (p, ov, ex, ex))
+                    return None
+
+
 if hasattr(os, "lstat"):
 
     def lstat(p: str) -> os.stat_result:
diff --git a/copyparty/ftpd.py b/copyparty/ftpd.py
index b0eb8736..ed18a0e7 100644
--- a/copyparty/ftpd.py
+++ b/copyparty/ftpd.py
@@ -409,12 +409,8 @@ class FtpFs(AbstractedFS):
             return st
 
     def utime(self, path: str, timeval: float) -> None:
-        try:
-            ap = self.rv2a(path, w=True)[0]
-            return bos.utime(ap, (int(time.time()), int(timeval)))
-        except Exception as ex:
-            logging.error("ftp.utime: %s, %r", ex, ex)
-            raise
+        ap = self.rv2a(path, w=True)[0]
+        bos.utime_c(logging.warning, ap, int(timeval), False)
 
     def lstat(self, path: str) -> os.stat_result:
         ap = self.rv2a(path)[0]
diff --git a/copyparty/httpcli.py b/copyparty/httpcli.py
index a379f655..072c5962 100644
--- a/copyparty/httpcli.py
+++ b/copyparty/httpcli.py
@@ -2329,12 +2329,7 @@ class HttpCli(object):
         at = mt = time.time() - lifetime
         cli_mt = self.headers.get("x-oc-mtime")
         if cli_mt:
-            try:
-                mt = int(cli_mt)
-                times = (int(time.time()), mt)
-                bos.utime(path, times, False)
-            except:
-                pass
+            bos.utime_c(self.log, path, int(cli_mt), False)
 
         if nameless and "magic" in vfs.flags:
             try:
diff --git a/copyparty/smbd.py b/copyparty/smbd.py
index 7caec6cc..3fbc1130 100644
--- a/copyparty/smbd.py
+++ b/copyparty/smbd.py
@@ -373,7 +373,7 @@ class SMB(object):
             t = "blocked utime (no-write-acc %s): /%s @%s"
             yeet(t % (vfs.axs.uwrite, vpath, uname))
 
-        return bos.utime(ap, times)
+        bos.utime_c(info, ap, int(times[1]), False)
 
     def _p_exists(self, vpath: str) -> bool:
         # ap = "?"
diff --git a/copyparty/up2k.py b/copyparty/up2k.py
index 1fc52333..1486ac17 100644
--- a/copyparty/up2k.py
+++ b/copyparty/up2k.py
@@ -3435,10 +3435,9 @@ class Up2k(object):
                     cur.connection.commit()
 
                     ap = djoin(job["ptop"], job["prel"], job["name"])
-                    times = (int(time.time()), int(cj["lmod"]))
-                    bos.utime(ap, times, False)
+                    mt = bos.utime_c(self.log, ap, int(cj["lmod"]), False, True)
 
-                    self.log("touched %r from %d to %d" % (ap, job["lmod"], cj["lmod"]))
+                    self.log("touched %r from %d to %d" % (ap, job["lmod"], mt))
                 except Exception as ex:
                     self.log("umod failed, %r" % (ex,), 3)
 
@@ -3593,8 +3592,7 @@ class Up2k(object):
             shutil.copy2(fsenc(csrc), fsenc(dst))
 
         if lmod and (not linked or SYMTIME):
-            times = (int(time.time()), int(lmod))
-            bos.utime(dst, times, False)
+            bos.utime_c(self.log, dst, int(lmod), False)
 
     def handle_chunks(
         self, ptop: str, wark: str, chashes: list[str]
@@ -3767,10 +3765,8 @@ class Up2k(object):
         times = (int(time.time()), int(job["lmod"]))
         t = "no more chunks, setting times %s (%d) on %r"
         self.log(t % (times, bos.path.getsize(dst), dst))
-        try:
-            bos.utime(dst, times)
-        except:
-            self.log("failed to utime (%r, %s)" % (dst, times))
+        bos.utime_c(self.log, dst, times[1], False)
+        # the above logmsg (and associated logic) is retained due to unforget.py
 
         zs = "prel name lmod size ptop vtop wark dwrk host user addr"
         z2 = [job[x] for x in zs.split()]
@@ -4919,7 +4915,10 @@ class Up2k(object):
             mt = bos.path.getmtime(slabs, False)
             flags = self.flags.get(ptop) or {}
             atomic_move(self.log, sabs, slabs, flags)
-            bos.utime(slabs, (int(time.time()), int(mt)), False)
+            try:
+                bos.utime(slabs, (int(time.time()), int(mt)), False)
+            except:
+                self.log("relink: failed to utime(%r, %s)" % (slabs, mt), 3)
             self._symlink(slabs, sabs, flags, False, is_mv=True)
             full[slabs] = (ptop, rem)
             sabs = slabs