diff --git a/CHANGES b/CHANGES
index a9d0ddc688..792dcb62b5 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,11 @@
+8.1.0-dev.664 | 2025-10-10 09:19:40 -0700
+
+  * Skip setting tm_gmtoff on Windows (Tim Wojtulewicz, Corelight)
+
+    tm_gmtoff is a POSIX extension to the tm struct that Windows doesn't
+    support it. It doesn't appear to change the output from the btest,
+    so we can just skip it.
+
 8.1.0-dev.662 | 2025-10-10 12:52:02 +0200
 
   * Bump CI to freebsd-13.5 (Benjamin Bannier, Corelight)
diff --git a/VERSION b/VERSION
index 0e195a8f76..f4c5c4bece 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-8.1.0-dev.662
+8.1.0-dev.664
diff --git a/src/analyzer/protocol/smb/smb-time.pac b/src/analyzer/protocol/smb/smb-time.pac
index a4fcd01dc1..1cbd7ec75b 100644
--- a/src/analyzer/protocol/smb/smb-time.pac
+++ b/src/analyzer/protocol/smb/smb-time.pac
@@ -33,9 +33,12 @@ double time_from_lanman(uint32_t smb_time, uint32_t smb_date, uint16_t tz)
 	lTime.tm_year = ((smb_date >> 9) & 0x7f) + 80;
 	lTime.tm_isdst = -1;
 
+#ifndef _MSC_VER
 	// The timezone passed in the data is the number of minutes from UTC, while
-	// tm_gmtoff is the number of seconds east of UTC. Adjust for that.
+	// tm_gmtoff is the number of seconds east of UTC. Adjust for that. This field
+	// is a POSIX extension that Windows doesn't support.
 	lTime.tm_gmtoff = static_cast<long>(tz) * 60;
+#endif
 
 	return timegm(&lTime);
 	}