Add note to all SDKs

source/sdk/dotnet/realm-files/encrypt-a-realm.txt

@@ -28,6 +28,13 @@ integrity using a :wikipedia:`hash-based message authentication code
 
 .. include:: /includes/encrypt-use-strong-cryptographic-hash.rst
 
+.. note:: Cannot Encrypt an Existing Unencrypted Realm
+
+    You *cannot* encrypt an existing unencrypted realm. 
+    If you pass an encryption key to a configuration
+    that does not already have one, Realm throws an 
+    error when you attempt to open the existing realm.
+
 Considerations
 --------------
 

source/sdk/flutter/realm-database/realm-files/encrypt.txt

@@ -27,6 +27,18 @@ integrity using a :wikipedia:`hash-based message authentication code
 
 .. include:: /includes/encrypt-use-strong-cryptographic-hash.rst
 
+.. note:: Cannot Encrypt an Existing Unencrypted Realm
+
+    You *cannot* encrypt an existing unencrypted realm. 
+    If you pass an encryption key to a configuration
+    that does not already have one, Realm throws an 
+    error when you attempt to open the existing realm.
+
+    You can copy an unencrypted realm to a new 
+    encrypted realm using the 
+    :flutter-sdk:`Realm.writeCopy() <realm/Realm/writeCopy.html>`method.
+    Refer to :ref:`<flutter-copy-data-into-new-realm>` for more information.
+
 Considerations
 --------------
 

source/sdk/kotlin/realm-database/realm-files/encrypt-a-realm.txt

@@ -12,8 +12,8 @@ Encrypt a Realm - Kotlin SDK
 
 You can encrypt your realms to ensure that the data stored to disk can't be 
 read outside of your application. You encrypt the realm file on 
-disk with AES-256 + SHA-2 by supplying a 64-byte encryption key when 
-:ref:`opening the realm <kotlin-open-and-close-a-realm>`.
+disk with AES-256 + SHA-2 by supplying a 64-byte encryption key when first
+:ref:`opening the realm <kotlin-open-and-close-a-realm>`. 
 
 Realm transparently encrypts and decrypts data with standard
 :wikipedia:`AES-256 encryption <Advanced_Encryption_Standard>` using the
@@ -24,13 +24,27 @@ integrity using a :wikipedia:`hash-based message authentication code
 
 .. include:: /includes/encrypt-use-strong-cryptographic-hash.rst
 
+.. note:: Cannot Encrypt an Existing Unencrypted Realm
+
+    You *cannot* encrypt an existing unencrypted realm. 
+    If you pass an encryption key to a configuration
+    that does not already have one, Realm throws an 
+    error when you attempt to open the existing realm.
+
+    Instead, you can copy the unencrypted realm data to a new 
+    encrypted realm using the 
+    `Realm.writeCopyTo() <{+kotlin-local-prefix+}io.realm.kotlin/-realm/write-copy-to.html>`__ 
+    method.
+    Refer to :ref:`<kotlin-copy-data-to-realm>` for more information.
+
 Encrypt a Local Realm
 ---------------------
 
 To encrypt a local realm, pass your encryption key to the
 `encryptionKey <{+kotlin-local-prefix+}io.realm.kotlin/-configuration/encryption-key.html>`__
-property in your 
-`RealmConfiguration.Builder() <{+kotlin-local-prefix+}io.realm.kotlin/-realm-configuration/index.html>`__.
+property in the 
+`RealmConfiguration.Builder() <{+kotlin-local-prefix+}io.realm.kotlin/-realm-configuration/index.html>`__
+used to open the realm. 
 
 The following code demonstrates how to generate an encryption key and
 open an encrypted local realm:
@@ -44,21 +58,24 @@ open an encrypted local realm:
 Encrypt a Synced Realm
 ----------------------
 
-You can encrypt a :ref:`synced realm <kotlin-open-a-synced-realm>`, similar
+If your app uses Atlas Device Sync, you can encrypt a synced realm, similar 
 to encrypting a local realm. 
 
 To encrypt a synced realm, pass your encryption key to the
 `encryptionKey <{+kotlin-sync-prefix+}io.realm.kotlin.mongodb/-app-configuration/encryption-key.html>`__
-property in your 
+property in the 
 `SyncConfiguration.Builder()
-<{+kotlin-sync-prefix+}io.realm.kotlin.mongodb.sync/-sync-configuration/-builder/-builder.html>`__.
+<{+kotlin-sync-prefix+}io.realm.kotlin.mongodb.sync/-sync-configuration/-builder/-builder.html>`__
+used to open the realm.
 
 The following code demonstrates how to open an encrypted synced realm:
 
 .. literalinclude:: /examples/generated/kotlin/EncryptARealmTest.snippet.encrypt-synced-realm.kt
    :language: kotlin
    :emphasize-lines: 5-6
 
+Refer to :ref:`<kotlin-open-a-synced-realm>` for more information. 
+
 Encryption and Atlas Device Sync
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
@@ -97,8 +114,8 @@ Performance Impact
 
 Reads and writes on encrypted realms can be up to 10% slower than unencrypted realms.
 
-Access Encrypted Realm from Multiple Processes
-----------------------------------------------
+Access Encrypted Realms from Multiple Processes
+-----------------------------------------------
 
 .. versionchanged:: 10.8.0
 

source/sdk/node/realm-files/encrypt.txt

@@ -23,6 +23,20 @@ integrity using a :wikipedia:`hash-based message authentication code
 
 .. include:: /includes/encrypt-use-strong-cryptographic-hash.rst
 
+.. note:: Cannot Encrypt an Existing Unencrypted Realm
+
+    You *cannot* encrypt an existing unencrypted realm. 
+    If you pass an encryption key to a configuration
+    that does not already have one, Realm throws an 
+    error when you attempt to open the existing realm.
+
+    You can copy an unencrypted realm to a new 
+    encrypted realm using the 
+    :js-sdk:`Realm.writeCopyTo() <Realm.html#writeCopyTo>`
+    method.
+    Refer to :ref:`<node-open-existing-realm-different-configuration>`
+    for more information.
+
 The following code demonstrates how to generate an encryption key and
 open an encrypted realm:
 

source/sdk/react-native/realm-files/encrypt.txt

@@ -22,6 +22,13 @@ integrity using a :wikipedia:`hash-based message authentication code
 
 .. include:: /includes/encrypt-use-strong-cryptographic-hash.rst
 
+.. note:: Cannot Encrypt an Existing Unencrypted Realm
+
+    You *cannot* encrypt an existing unencrypted realm. 
+    If you pass an encryption key to a configuration
+    that does not already have one, Realm throws an 
+    error when you attempt to open the existing realm.
+
 The following code demonstrates how to generate an encryption key and
 open an encrypted realm:
 

source/sdk/swift/realm-files/encrypt-a-realm.txt

@@ -26,6 +26,13 @@ integrity using a :wikipedia:`hash-based message authentication code
 
 .. include:: /includes/encrypt-use-strong-cryptographic-hash.rst
 
+.. note:: Cannot Encrypt an Existing Unencrypted Realm
+
+    You *cannot* encrypt an existing unencrypted realm. 
+    If you pass an encryption key to a configuration
+    that does not already have one, Realm throws an 
+    error when you attempt to open the existing realm.
+
 Considerations
 --------------