diff --git a/Ghidra/Features/FileFormats/src/main/java/ghidra/file/formats/ios/dmg/DmgClientFileSystemFactory.java b/Ghidra/Features/FileFormats/src/main/java/ghidra/file/formats/ios/dmg/DmgClientFileSystemFactory.java
index 909b5b6470..d00585282a 100644
--- a/Ghidra/Features/FileFormats/src/main/java/ghidra/file/formats/ios/dmg/DmgClientFileSystemFactory.java
+++ b/Ghidra/Features/FileFormats/src/main/java/ghidra/file/formats/ios/dmg/DmgClientFileSystemFactory.java
@@ -21,7 +21,6 @@ import java.io.IOException;
 import generic.jar.ResourceFile;
 import ghidra.app.util.bin.ByteProvider;
 import ghidra.file.formats.xar.XARUtil;
-import ghidra.file.formats.zlib.ZLIB;
 import ghidra.formats.gfilesystem.*;
 import ghidra.formats.gfilesystem.factory.GFileSystemFactoryWithFile;
 import ghidra.formats.gfilesystem.factory.GFileSystemProbeFull;
@@ -46,7 +45,7 @@ public class DmgClientFileSystemFactory
 	@Override
 	public boolean probe(FSRL containerFSRL, ByteProvider byteProvider, File containerFile,
 			FileSystemService fsService, TaskMonitor taskMonitor)
-					throws IOException, CancelledException {
+			throws IOException, CancelledException {
 
 		if (!isDmgPresent()) {
 			return false;
@@ -56,9 +55,6 @@ public class DmgClientFileSystemFactory
 		if (XARUtil.isXAR(byteProvider)) {
 			return false;
 		}
-		if (ZLIB.isZLIB(byteProvider)) {
-			return true;
-		}
 
 		return isEncrypted(containerFile);
 	}
@@ -84,7 +80,7 @@ public class DmgClientFileSystemFactory
 	@Override
 	public DmgClientFileSystem create(FSRL containerFSRL, FSRLRoot targetFSRL, File containerFile,
 			FileSystemService fsService, TaskMonitor monitor)
-					throws IOException, CancelledException {
+			throws IOException, CancelledException {
 
 		String dmgName = containerFSRL.getName();
 
@@ -103,7 +99,7 @@ public class DmgClientFileSystemFactory
 				fsService.getDerivedFile(containerFSRL, "decrypted " + containerName, (srcFile) -> {
 					monitor.initialize(srcFile.length());
 					return new DmgDecryptorStream(containerName, dmgName, srcFile);
-				} , monitor);
+				}, monitor);
 			decrypted_dmg_file = fce.file;
 		}
 		else {
diff --git a/Ghidra/Features/FileFormats/src/main/java/ghidra/file/formats/ios/dmg/DmgDecryptorStream.java b/Ghidra/Features/FileFormats/src/main/java/ghidra/file/formats/ios/dmg/DmgDecryptorStream.java
index 0cf7a7251b..6d088c0552 100644
--- a/Ghidra/Features/FileFormats/src/main/java/ghidra/file/formats/ios/dmg/DmgDecryptorStream.java
+++ b/Ghidra/Features/FileFormats/src/main/java/ghidra/file/formats/ios/dmg/DmgDecryptorStream.java
@@ -15,15 +15,15 @@
  */
 package ghidra.file.formats.ios.dmg;
 
+import java.io.*;
+import java.util.Arrays;
+
 import ghidra.app.util.bin.*;
 import ghidra.file.crypto.*;
 import ghidra.file.formats.ios.generic.iOS_AesCrypto;
 import ghidra.file.formats.ios.generic.iOS_Sha1Crypto;
 import ghidra.util.exception.CryptoException;
 
-import java.io.*;
-import java.util.Arrays;
-
 /**
  * An {@link InputStream} that decrypts a DMG file on the fly.
  * <p>
@@ -76,19 +76,32 @@ public class DmgDecryptorStream extends InputStream {
 	public DmgDecryptorStream(String containerName, String dmgName, ByteProvider provider)
 			throws IOException {
 
+		try {
+			CryptoKey cryptoKey = CryptoKeyFactory.getCryptoKey(containerName, dmgName);
+			if (cryptoKey.key.length != 36) {
+				throw new CryptoException("Invalid key length.");
+			}
+			if (cryptoKey.iv.length != 0) {
+				throw new CryptoException("Invalid initialization vector (IV) length.");
+			}
+
+			aes_key = Arrays.copyOfRange(cryptoKey.key, 0, 16);
+			sha1_key = Arrays.copyOfRange(cryptoKey.key, 16, 16 + 20);
+		}
+		catch (IOException e) {
+			// Release the provider before this exception finishes since the #close() method can't
+			// be called later to release it.
+			try {
+				provider.close();
+			}
+			catch (IOException ioe) {
+				// ignore
+			}
+			throw e;
+		}
+
 		this.provider = provider;
 
-		CryptoKey cryptoKey = CryptoKeyFactory.getCryptoKey(containerName, dmgName);
-		if (cryptoKey.key.length != 36) {
-			throw new CryptoException("Invalid key length.");
-		}
-		if (cryptoKey.iv.length != 0) {
-			throw new CryptoException("Invalid initialization vector (IV) length.");
-		}
-
-		aes_key = Arrays.copyOfRange(cryptoKey.key, 0, 16);
-		sha1_key = Arrays.copyOfRange(cryptoKey.key, 16, 16 + 20);
-
 		sha1 = new iOS_Sha1Crypto(sha1_key);
 
 		BinaryReader reader = new BinaryReader(provider, false);