diff --git a/changelog.d/5663.bugfix b/changelog.d/5663.bugfix
new file mode 100644
index 0000000000..5086407e8e
--- /dev/null
+++ b/changelog.d/5663.bugfix
@@ -0,0 +1 @@
+Fixed key export when overwriting existing files
diff --git a/vector/src/main/java/im/vector/app/features/crypto/keys/KeysExporter.kt b/vector/src/main/java/im/vector/app/features/crypto/keys/KeysExporter.kt
index 3db67df8e1..27d8d4842a 100644
--- a/vector/src/main/java/im/vector/app/features/crypto/keys/KeysExporter.kt
+++ b/vector/src/main/java/im/vector/app/features/crypto/keys/KeysExporter.kt
@@ -34,7 +34,7 @@ class KeysExporter @Inject constructor(
     suspend fun export(password: String, uri: Uri) {
         withContext(dispatchers.io) {
             val data = session.cryptoService().exportRoomKeys(password)
-            context.contentResolver.openOutputStream(uri)
+            context.contentResolver.openOutputStream(uri, "wt")
                     ?.use { it.write(data) }
                     ?: throw IllegalStateException("Unable to open file for writing")
             verifyExportedKeysOutputFileSize(uri, expectedSize = data.size.toLong())
diff --git a/vector/src/main/java/im/vector/app/features/crypto/keysbackup/setup/KeysBackupSetupStep3Fragment.kt b/vector/src/main/java/im/vector/app/features/crypto/keysbackup/setup/KeysBackupSetupStep3Fragment.kt
index c1cd87b4c8..42ff4ac183 100644
--- a/vector/src/main/java/im/vector/app/features/crypto/keysbackup/setup/KeysBackupSetupStep3Fragment.kt
+++ b/vector/src/main/java/im/vector/app/features/crypto/keysbackup/setup/KeysBackupSetupStep3Fragment.kt
@@ -165,7 +165,7 @@ class KeysBackupSetupStep3Fragment @Inject constructor() : VectorBaseFragment<Fr
         lifecycleScope.launch(Dispatchers.Main) {
             Try {
                 withContext(Dispatchers.IO) {
-                    requireContext().contentResolver.openOutputStream(uri)
+                    requireContext().contentResolver.openOutputStream(uri, "wt")
                             ?.use { os ->
                                 os.write(data.toByteArray())
                                 os.flush()
diff --git a/vector/src/main/java/im/vector/app/features/crypto/recover/BootstrapSaveRecoveryKeyFragment.kt b/vector/src/main/java/im/vector/app/features/crypto/recover/BootstrapSaveRecoveryKeyFragment.kt
index 8a41c7ce4d..746ed48c94 100644
--- a/vector/src/main/java/im/vector/app/features/crypto/recover/BootstrapSaveRecoveryKeyFragment.kt
+++ b/vector/src/main/java/im/vector/app/features/crypto/recover/BootstrapSaveRecoveryKeyFragment.kt
@@ -81,7 +81,7 @@ class BootstrapSaveRecoveryKeyFragment @Inject constructor(
             val uri = activityResult.data?.data ?: return@registerStartForActivityResult
             lifecycleScope.launch(Dispatchers.IO) {
                 try {
-                    sharedViewModel.handle(BootstrapActions.SaveKeyToUri(requireContext().contentResolver!!.openOutputStream(uri)!!))
+                    sharedViewModel.handle(BootstrapActions.SaveKeyToUri(requireContext().contentResolver!!.openOutputStream(uri, "wt")!!))
                 } catch (failure: Throwable) {
                     sharedViewModel.handle(BootstrapActions.SaveReqFailed)
                 }
diff --git a/vector/src/main/java/im/vector/app/features/settings/devtools/KeyRequestsFragment.kt b/vector/src/main/java/im/vector/app/features/settings/devtools/KeyRequestsFragment.kt
index db2d07feef..6748fec1bc 100644
--- a/vector/src/main/java/im/vector/app/features/settings/devtools/KeyRequestsFragment.kt
+++ b/vector/src/main/java/im/vector/app/features/settings/devtools/KeyRequestsFragment.kt
@@ -106,7 +106,7 @@ class KeyRequestsFragment @Inject constructor() : VectorBaseFragment<FragmentDev
             when (it) {
                 is KeyRequestEvents.SaveAudit -> {
                     tryOrNull {
-                        requireContext().contentResolver?.openOutputStream(it.uri)
+                        requireContext().contentResolver?.openOutputStream(it.uri, "wt")
                                 ?.use { os -> os.write(it.raw.toByteArray()) }
                     }
                 }
diff --git a/vector/src/test/java/im/vector/app/features/crypto/keys/KeysExporterTest.kt b/vector/src/test/java/im/vector/app/features/crypto/keys/KeysExporterTest.kt
index 5d0317592d..3bec3fad88 100644
--- a/vector/src/test/java/im/vector/app/features/crypto/keys/KeysExporterTest.kt
+++ b/vector/src/test/java/im/vector/app/features/crypto/keys/KeysExporterTest.kt
@@ -53,7 +53,7 @@ class KeysExporterTest {
     @Test
     fun `when exporting then writes exported keys to context output stream`() {
         givenFileDescriptorWithSize(size = A_ROOM_KEYS_EXPORT.size.toLong())
-        val outputStream = context.givenOutputStreamFor(A_URI)
+        val outputStream = context.givenOutputStreamFor(A_URI, mode = "wt")
 
         runTest { keysExporter.export(A_PASSWORD, A_URI) }
 
@@ -63,7 +63,7 @@ class KeysExporterTest {
     @Test
     fun `given different file size returned for export when exporting then throws UnexpectedExportKeysFileSizeException`() {
         givenFileDescriptorWithSize(size = 110)
-        context.givenOutputStreamFor(A_URI)
+        context.givenOutputStreamFor(A_URI, mode = "wt")
 
         assertFailsWith<UnexpectedExportKeysFileSizeException> {
             runTest { keysExporter.export(A_PASSWORD, A_URI) }
@@ -72,7 +72,7 @@ class KeysExporterTest {
 
     @Test
     fun `given output stream is unavailable for exporting to when exporting then throws IllegalStateException`() {
-        context.givenMissingOutputStreamFor(A_URI)
+        context.givenMissingOutputStreamFor(A_URI, mode = "wt")
 
         assertFailsWith<IllegalStateException>(message = "Unable to open file for writing") {
             runTest { keysExporter.export(A_PASSWORD, A_URI) }
@@ -82,7 +82,7 @@ class KeysExporterTest {
     @Test
     fun `given exported file is missing after export when exporting then throws IllegalStateException`() {
         context.givenFileDescriptor(A_URI, mode = "r") { null }
-        context.givenOutputStreamFor(A_URI)
+        context.givenOutputStreamFor(A_URI, mode = "wt")
 
         assertFailsWith<IllegalStateException>(message = "Exported file not found") {
             runTest { keysExporter.export(A_PASSWORD, A_URI) }
diff --git a/vector/src/test/java/im/vector/app/test/fakes/FakeContext.kt b/vector/src/test/java/im/vector/app/test/fakes/FakeContext.kt
index 8382e54253..de1a7956b8 100644
--- a/vector/src/test/java/im/vector/app/test/fakes/FakeContext.kt
+++ b/vector/src/test/java/im/vector/app/test/fakes/FakeContext.kt
@@ -39,13 +39,13 @@ class FakeContext(
         every { contentResolver.openFileDescriptor(uri, mode, null) } returns fileDescriptor
     }
 
-    fun givenOutputStreamFor(uri: Uri): OutputStream {
+    fun givenOutputStreamFor(uri: Uri, mode: String): OutputStream {
         val outputStream = mockk<OutputStream>(relaxed = true)
-        every { contentResolver.openOutputStream(uri) } returns outputStream
+        every { contentResolver.openOutputStream(uri, mode) } returns outputStream
         return outputStream
     }
 
-    fun givenMissingOutputStreamFor(uri: Uri) {
-        every { contentResolver.openOutputStream(uri) } returns null
+    fun givenMissingOutputStreamFor(uri: Uri, mode: String) {
+        every { contentResolver.openOutputStream(uri, mode) } returns null
     }
 }