Fixes #176

Author: infeo

src/main/java/org/cryptomator/cryptofs/CryptoFileSystemImpl.java

@@ -18,6 +18,7 @@
 import org.cryptomator.cryptofs.common.DeletingFileVisitor;
 import org.cryptomator.cryptofs.common.FinallyUtil;
 import org.cryptomator.cryptofs.dir.CiphertextDirectoryDeleter;
+import org.cryptomator.cryptofs.dir.DirIdBackupFilter;
 import org.cryptomator.cryptofs.dir.DirectoryStreamFactory;
 import org.cryptomator.cryptofs.fh.OpenCryptoFiles;
 import org.cryptomator.cryptolib.api.Cryptor;
@@ -623,7 +624,7 @@ private void moveDirectory(CryptoPath cleartextSource, CryptoPath cleartextTarge
 			// check if dir is empty:
 			Path targetCiphertextDirContentDir = cryptoPathMapper.getCiphertextDir(cleartextTarget).path;
 			boolean targetCiphertextDirExists = true;
-			try (DirectoryStream<Path> ds = Files.newDirectoryStream(targetCiphertextDirContentDir)) {
+			try (DirectoryStream<Path> ds = Files.newDirectoryStream(targetCiphertextDirContentDir, new DirIdBackupFilter())) {
 				if (ds.iterator().hasNext()) {
 					throw new DirectoryNotEmptyException(cleartextTarget.toString());
 				}

src/main/java/org/cryptomator/cryptofs/dir/DirIdBackupFilter.java

@@ -0,0 +1,18 @@
+package org.cryptomator.cryptofs.dir;
+
+import org.cryptomator.cryptofs.common.Constants;
+
+import java.io.IOException;
+import java.nio.file.DirectoryStream;
+import java.nio.file.Path;
+
+public class DirIdBackupFilter implements DirectoryStream.Filter<Path> {
+
+	private final Path skippedEntry = Path.of(Constants.DIR_BACKUP_FILE_NAME);
+
+	@Override
+	public boolean accept(Path entry) throws IOException {
+		return entry.getFileName().equals(skippedEntry);
+	}
+
+}