diff --git a/weed/s3api/s3api_object_handlers_conditional_write_test.go b/weed/s3api/s3api_object_handlers_conditional_write_test.go
new file mode 100644
index 0000000000..fb329c06cb
--- /dev/null
+++ b/weed/s3api/s3api_object_handlers_conditional_write_test.go
@@ -0,0 +1,58 @@
+package s3api
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
+	"github.com/seaweedfs/seaweedfs/weed/s3api/s3_constants"
+	"github.com/seaweedfs/seaweedfs/weed/s3api/s3err"
+)
+
+// A conditional write with If-Match has nothing to compare against when the key has
+// no current version; AWS answers 404 there, not 412.
+func TestValidateConditionalHeadersMissingObject(t *testing.T) {
+	s3a := &S3ApiServer{}
+
+	existing := &filer_pb.Entry{
+		Attributes: &filer_pb.FuseAttributes{Mtime: time.Now().Unix()},
+		Extended:   map[string][]byte{s3_constants.ExtETagKey: []byte("d41d8cd98f00b204e9800998ecf8427e")},
+	}
+	deleteMarker := &filer_pb.Entry{
+		Attributes: &filer_pb.FuseAttributes{Mtime: time.Now().Unix()},
+		Extended:   map[string][]byte{s3_constants.ExtDeleteMarkerKey: []byte("true")},
+	}
+
+	testCases := []struct {
+		name   string
+		header string
+		value  string
+		entry  *filer_pb.Entry
+		want   s3err.ErrorCode
+	}{
+		{"if-match on missing object", s3_constants.IfMatch, "d41d8cd98f00b204e9800998ecf8427e", nil, s3err.ErrNoSuchKey},
+		{"if-match star on missing object", s3_constants.IfMatch, "*", nil, s3err.ErrNoSuchKey},
+		{"if-match on delete marker", s3_constants.IfMatch, "d41d8cd98f00b204e9800998ecf8427e", deleteMarker, s3err.ErrNoSuchKey},
+		{"if-match mismatch on existing object", s3_constants.IfMatch, "0000", existing, s3err.ErrPreconditionFailed},
+		{"if-match hit on existing object", s3_constants.IfMatch, "d41d8cd98f00b204e9800998ecf8427e", existing, s3err.ErrNone},
+		{"if-none-match star on missing object", s3_constants.IfNoneMatch, "*", nil, s3err.ErrNone},
+		{"if-none-match star on delete marker", s3_constants.IfNoneMatch, "*", deleteMarker, s3err.ErrNone},
+		{"if-none-match star on existing object", s3_constants.IfNoneMatch, "*", existing, s3err.ErrPreconditionFailed},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			r := httptest.NewRequest(http.MethodPut, "/bucket/object", nil)
+			r.Header.Set(tc.header, tc.value)
+			headers, errCode := parseConditionalHeaders(r)
+			if errCode != s3err.ErrNone {
+				t.Fatalf("parseConditionalHeaders: %v", errCode)
+			}
+			if got := s3a.validateConditionalHeaders(r, headers, tc.entry, "bucket", "object"); got != tc.want {
+				t.Errorf("got %v, want %v", got, tc.want)
+			}
+		})
+	}
+}
diff --git a/weed/s3api/s3api_object_handlers_put.go b/weed/s3api/s3api_object_handlers_put.go
index e8530950e0..3b895f9260 100644
--- a/weed/s3api/s3api_object_handlers_put.go
+++ b/weed/s3api/s3api_object_handlers_put.go
@@ -2796,8 +2796,9 @@ func (s3a *S3ApiServer) validateConditionalHeaders(r *http.Request, headers cond
 
 	// 1. Check If-Match
 	if headers.ifMatch != "" {
+		// AWS answers 404 when there is no current version (or it is a delete marker)
 		if !objectExists {
-			return s3err.ErrPreconditionFailed
+			return s3err.ErrNoSuchKey
 		}
 		// If `ifMatch` is "*", the condition is met if the object exists.
 		// Otherwise, we need to check the ETag.