diff --git a/lib/db/lowlevel.go b/lib/db/lowlevel.go
index e00b9dcfa..ff4062fe9 100644
--- a/lib/db/lowlevel.go
+++ b/lib/db/lowlevel.go
@@ -201,7 +201,7 @@ func (db *Lowlevel) updateLocalFiles(folder []byte, fs []protocol.FileInfo, meta
 		blocksHashSame := ok && bytes.Equal(ef.BlocksHash, f.BlocksHash)
 
 		if ok {
-			if len(ef.Blocks) != 0 && !ef.IsInvalid() {
+			if len(ef.Blocks) != 0 && !ef.IsInvalid() && ef.Size > 0 {
 				for _, block := range ef.Blocks {
 					keyBuf, err = db.keyer.GenerateBlockMapKey(keyBuf, folder, block.Hash, name)
 					if err != nil {
@@ -262,7 +262,7 @@ func (db *Lowlevel) updateLocalFiles(folder []byte, fs []protocol.FileInfo, meta
 		}
 		l.Debugf("adding sequence; folder=%q sequence=%v %v", folder, f.Sequence, f.Name)
 
-		if len(f.Blocks) != 0 && !f.IsInvalid() {
+		if len(f.Blocks) != 0 && !f.IsInvalid() && f.Size > 0 {
 			for i, block := range f.Blocks {
 				binary.BigEndian.PutUint32(blockBuf, uint32(i))
 				keyBuf, err = db.keyer.GenerateBlockMapKey(keyBuf, folder, block.Hash, name)
diff --git a/lib/db/set_test.go b/lib/db/set_test.go
index 5a475b150..b6b2cd777 100644
--- a/lib/db/set_test.go
+++ b/lib/db/set_test.go
@@ -484,11 +484,11 @@ func TestUpdateToInvalid(t *testing.T) {
 	f := db.NewBlockFinder(ldb)
 
 	localHave := fileList{
-		protocol.FileInfo{Name: "a", Version: protocol.Vector{Counters: []protocol.Counter{{ID: myID, Value: 1000}}}, Blocks: genBlocks(1)},
-		protocol.FileInfo{Name: "b", Version: protocol.Vector{Counters: []protocol.Counter{{ID: myID, Value: 1001}}}, Blocks: genBlocks(2)},
-		protocol.FileInfo{Name: "c", Version: protocol.Vector{Counters: []protocol.Counter{{ID: myID, Value: 1002}}}, Blocks: genBlocks(5), LocalFlags: protocol.FlagLocalIgnored},
-		protocol.FileInfo{Name: "d", Version: protocol.Vector{Counters: []protocol.Counter{{ID: myID, Value: 1003}}}, Blocks: genBlocks(7)},
-		protocol.FileInfo{Name: "e", Version: protocol.Vector{Counters: []protocol.Counter{{ID: myID, Value: 1003}}}, LocalFlags: protocol.FlagLocalIgnored},
+		protocol.FileInfo{Name: "a", Version: protocol.Vector{Counters: []protocol.Counter{{ID: myID, Value: 1000}}}, Blocks: genBlocks(1), Size: 1},
+		protocol.FileInfo{Name: "b", Version: protocol.Vector{Counters: []protocol.Counter{{ID: myID, Value: 1001}}}, Blocks: genBlocks(2), Size: 1},
+		protocol.FileInfo{Name: "c", Version: protocol.Vector{Counters: []protocol.Counter{{ID: myID, Value: 1002}}}, Blocks: genBlocks(5), LocalFlags: protocol.FlagLocalIgnored, Size: 1},
+		protocol.FileInfo{Name: "d", Version: protocol.Vector{Counters: []protocol.Counter{{ID: myID, Value: 1003}}}, Blocks: genBlocks(7), Size: 1},
+		protocol.FileInfo{Name: "e", Version: protocol.Vector{Counters: []protocol.Counter{{ID: myID, Value: 1003}}}, LocalFlags: protocol.FlagLocalIgnored, Size: 1},
 	}
 
 	replace(s, protocol.LocalDeviceID, localHave)
diff --git a/lib/model/folder.go b/lib/model/folder.go
index c9b7d14fd..8db1dfb58 100644
--- a/lib/model/folder.go
+++ b/lib/model/folder.go
@@ -453,20 +453,27 @@ func (f *folder) scanSubdirs(subDirs []string) error {
 	}()
 
 	f.clearScanErrors(subDirs)
+	alreadyUsed := make(map[string]struct{})
 	for res := range fchan {
 		if res.Err != nil {
 			f.newScanError(res.Path, res.Err)
 			continue
 		}
-		if err := batch.flushIfFull(); err != nil {
-			return err
+
+		if batch.full() {
+			if err := batch.flush(); err != nil {
+				return err
+			}
+			snap.Release()
+			snap = f.fset.Snapshot()
+			alreadyUsed = make(map[string]struct{})
 		}
 
 		batch.append(res.File)
 		changes++
 
 		if f.localFlags&protocol.FlagLocalReceiveOnly == 0 {
-			if nf, ok := f.findRename(snap, mtimefs, res.File); ok {
+			if nf, ok := f.findRename(snap, mtimefs, res.File, alreadyUsed); ok {
 				batch.append(nf)
 				changes++
 			}
@@ -622,8 +629,8 @@ func (f *folder) scanSubdirs(subDirs []string) error {
 	return nil
 }
 
-func (f *folder) findRename(snap *db.Snapshot, mtimefs fs.Filesystem, file protocol.FileInfo) (protocol.FileInfo, bool) {
-	if len(file.Blocks) == 0 {
+func (f *folder) findRename(snap *db.Snapshot, mtimefs fs.Filesystem, file protocol.FileInfo, alreadyUsed map[string]struct{}) (protocol.FileInfo, bool) {
+	if len(file.Blocks) == 0 || file.Size == 0 {
 		return protocol.FileInfo{}, false
 	}
 
@@ -639,6 +646,10 @@ func (f *folder) findRename(snap *db.Snapshot, mtimefs fs.Filesystem, file proto
 		default:
 		}
 
+		if _, ok := alreadyUsed[fi.Name]; ok {
+			return true
+		}
+
 		if fi.ShouldConflict() {
 			return true
 		}
@@ -658,6 +669,8 @@ func (f *folder) findRename(snap *db.Snapshot, mtimefs fs.Filesystem, file proto
 			return true
 		}
 
+		alreadyUsed[fi.Name] = struct{}{}
+
 		nf = fi
 		nf.SetDeleted(f.shortID)
 		nf.LocalFlags = f.localFlags
diff --git a/lib/model/folder_sendrecv_test.go b/lib/model/folder_sendrecv_test.go
index b6dfb6f56..874fe570a 100644
--- a/lib/model/folder_sendrecv_test.go
+++ b/lib/model/folder_sendrecv_test.go
@@ -213,6 +213,7 @@ func TestCopierFinder(t *testing.T) {
 
 	existingBlocks := []int{0, 2, 3, 4, 0, 0, 7, 0}
 	existingFile := setupFile(fs.TempName("file"), existingBlocks)
+	existingFile.Size = 1
 	requiredFile := existingFile
 	requiredFile.Blocks = blocks[1:]
 	requiredFile.Name = "file2"
@@ -422,6 +423,7 @@ func TestCopierCleanup(t *testing.T) {
 
 	// Create a file
 	file := setupFile("test", []int{0})
+	file.Size = 1
 	m, f := setupSendReceiveFolder(file)
 	defer cleanupSRFolder(f, m)
 
diff --git a/lib/model/model_test.go b/lib/model/model_test.go
index a773f645b..7be967562 100644
--- a/lib/model/model_test.go
+++ b/lib/model/model_test.go
@@ -3609,6 +3609,132 @@ func TestRenameSequenceOrder(t *testing.T) {
 	}
 }
 
+func TestRenameSameFile(t *testing.T) {
+	wcfg, fcfg := tmpDefaultWrapper()
+	m := setupModel(wcfg)
+	defer cleanupModel(m)
+
+	ffs := fcfg.Filesystem()
+	must(t, writeFile(ffs, "file", []byte("file"), 0644))
+
+	m.ScanFolders()
+
+	count := 0
+	snap := dbSnapshot(t, m, "default")
+	snap.WithHave(protocol.LocalDeviceID, func(i db.FileIntf) bool {
+		count++
+		return true
+	})
+	snap.Release()
+
+	if count != 1 {
+		t.Errorf("Unexpected count: %d != %d", count, 1)
+	}
+
+	must(t, ffs.Rename("file", "file1"))
+	must(t, osutil.Copy(ffs, ffs, "file1", "file0"))
+	must(t, osutil.Copy(ffs, ffs, "file1", "file2"))
+	must(t, osutil.Copy(ffs, ffs, "file1", "file3"))
+	must(t, osutil.Copy(ffs, ffs, "file1", "file4"))
+
+	m.ScanFolders()
+
+	snap = dbSnapshot(t, m, "default")
+	defer snap.Release()
+
+	prevSeq := int64(0)
+	seen := false
+	snap.WithHaveSequence(0, func(i db.FileIntf) bool {
+		if i.SequenceNo() <= prevSeq {
+			t.Fatalf("non-increasing sequences: %d <= %d", i.SequenceNo(), prevSeq)
+		}
+		if i.FileName() == "file" {
+			if seen {
+				t.Fatal("already seen file")
+			}
+			seen = true
+		}
+		prevSeq = i.SequenceNo()
+		return true
+	})
+}
+
+func TestRenameEmptyFile(t *testing.T) {
+	wcfg, fcfg := tmpDefaultWrapper()
+	m := setupModel(wcfg)
+	defer cleanupModel(m)
+
+	ffs := fcfg.Filesystem()
+
+	must(t, writeFile(ffs, "file", []byte("data"), 0644))
+	must(t, writeFile(ffs, "empty", nil, 0644))
+
+	m.ScanFolders()
+
+	snap := dbSnapshot(t, m, "default")
+	defer snap.Release()
+	empty, eok := snap.Get(protocol.LocalDeviceID, "empty")
+	if !eok {
+		t.Fatal("failed to find empty file")
+	}
+	file, fok := snap.Get(protocol.LocalDeviceID, "file")
+	if !fok {
+		t.Fatal("failed to find non-empty file")
+	}
+
+	count := 0
+	snap.WithBlocksHash(empty.BlocksHash, func(_ db.FileIntf) bool {
+		count++
+		return true
+	})
+
+	if count != 0 {
+		t.Fatalf("Found %d entries for empty file, expected 0", count)
+	}
+
+	count = 0
+	snap.WithBlocksHash(file.BlocksHash, func(_ db.FileIntf) bool {
+		count++
+		return true
+	})
+
+	if count != 1 {
+		t.Fatalf("Found %d entries for non-empty file, expected 1", count)
+	}
+
+	must(t, ffs.Rename("file", "new-file"))
+	must(t, ffs.Rename("empty", "new-empty"))
+
+	// Scan
+	m.ScanFolders()
+
+	snap = dbSnapshot(t, m, "default")
+	defer snap.Release()
+
+	count = 0
+	snap.WithBlocksHash(empty.BlocksHash, func(_ db.FileIntf) bool {
+		count++
+		return true
+	})
+
+	if count != 0 {
+		t.Fatalf("Found %d entries for empty file, expected 0", count)
+	}
+
+	count = 0
+	snap.WithBlocksHash(file.BlocksHash, func(i db.FileIntf) bool {
+		count++
+		if i.FileName() != "new-file" {
+			t.Fatalf("unexpected file name %s, expected new-file", i.FileName())
+		}
+		return true
+	})
+
+	if count != 1 {
+		t.Fatalf("Found %d entries for non-empty file, expected 1", count)
+	}
+}
+
 func TestBlockListMap(t *testing.T) {
 	wcfg, fcfg := tmpDefaultWrapper()
 	m := setupModel(wcfg)