diff --git a/server/filestore.go b/server/filestore.go
index 8552c84b110..d29d51f88cd 100644
--- a/server/filestore.go
+++ b/server/filestore.go
@@ -4320,11 +4320,13 @@ func (mb *msgBlock) truncate(sm *StoreMsg) (nmsgs, nbytes uint64, err error) {
 	if mb.cmp != NoCompression {
 		buf, err := mb.loadBlock(nil)
 		if err != nil {
+			mb.mu.Unlock()
 			return 0, 0, fmt.Errorf("failed to load block from disk: %w", err)
 		}
 		if mb.bek != nil && len(buf) > 0 {
 			bek, err := genBlockEncryptionKey(mb.fs.fcfg.Cipher, mb.seed, mb.nonce)
 			if err != nil {
+				mb.mu.Unlock()
 				return 0, 0, err
 			}
 			mb.bek = bek
@@ -4332,12 +4334,14 @@ func (mb *msgBlock) truncate(sm *StoreMsg) (nmsgs, nbytes uint64, err error) {
 		}
 		buf, err = mb.decompressIfNeeded(buf)
 		if err != nil {
+			mb.mu.Unlock()
 			return 0, 0, fmt.Errorf("failed to decompress block: %w", err)
 		}
 		buf = buf[:eof]
 		copy(mb.lchk[0:], buf[:len(buf)-checksumSize])
 		buf, err = mb.cmp.Compress(buf)
 		if err != nil {
+			mb.mu.Unlock()
 			return 0, 0, fmt.Errorf("failed to recompress block: %w", err)
 		}
 		meta := &CompressionInfo{
@@ -4348,6 +4352,7 @@ func (mb *msgBlock) truncate(sm *StoreMsg) (nmsgs, nbytes uint64, err error) {
 		if mb.bek != nil && len(buf) > 0 {
 			bek, err := genBlockEncryptionKey(mb.fs.fcfg.Cipher, mb.seed, mb.nonce)
 			if err != nil {
+				mb.mu.Unlock()
 				return 0, 0, err
 			}
 			mb.bek = bek
@@ -4355,9 +4360,11 @@ func (mb *msgBlock) truncate(sm *StoreMsg) (nmsgs, nbytes uint64, err error) {
 		}
 		n, err := mb.writeAt(buf, 0)
 		if err != nil {
+			mb.mu.Unlock()
 			return 0, 0, fmt.Errorf("failed to rewrite compressed block: %w", err)
 		}
 		if n != len(buf) {
+			mb.mu.Unlock()
 			return 0, 0, fmt.Errorf("short write (%d != %d)", n, len(buf))
 		}
 		mb.mfd.Truncate(int64(len(buf)))
@@ -7008,6 +7015,7 @@ func (fs *fileStore) Truncate(seq uint64) error {
 	// Set lmb to nlmb and make sure writeable.
 	fs.lmb = nlmb
 	if err := nlmb.enableForWriting(fs.fip); err != nil {
+		fs.mu.Unlock()
 		return err
 	}
 
diff --git a/server/stream.go b/server/stream.go
index 0462a96787e..73694d2ed59 100644
--- a/server/stream.go
+++ b/server/stream.go
@@ -5611,6 +5611,7 @@ func (mset *stream) swapSigSubs(o *consumer, newFilters []string) {
 
 	if o.closed || o.mset == nil {
 		o.mu.Unlock()
+		mset.clsMu.Unlock()
 		return
 	}