diff --git a/common/src/main/java/com/microsoft/identity/common/exception/ErrorStrings.java b/common/src/main/java/com/microsoft/identity/common/exception/ErrorStrings.java
index 98907e0c9e..b54632534c 100644
--- a/common/src/main/java/com/microsoft/identity/common/exception/ErrorStrings.java
+++ b/common/src/main/java/com/microsoft/identity/common/exception/ErrorStrings.java
@@ -350,4 +350,34 @@ private ErrorStrings() {
      */
     public static final String KEY_NOT_FOUND = "key_not_found";
 
+    /**
+     * AccountMode in configuration is set to multiple. However, the device is marked as shared (which requires single account mode).
+     */
+    public static final String MULTIPLE_ACCOUNT_PCA_INIT_FAIL_ON_SHARED_DEVICE_ERROR_CODE = "multiple_account_pca_init_fail_on_shared_device";
+    public static final String MULTIPLE_ACCOUNT_PCA_INIT_FAIL_ON_SHARED_DEVICE_ERROR_MESSAGE = "AccountMode in configuration is set to multiple. However, the device is marked as shared (which requires single account mode).";
+
+    /**
+     * Multiple account PublicClientApplication could not be created for unknown reasons
+     */
+    public static final String MULTIPLE_ACCOUNT_PCA_INIT_FAIL_UNKNOWN_REASON_ERROR_CODE = "multiple_account_pca_init_fail_unknown_reason";
+    public static final String MULTIPLE_ACCOUNT_PCA_INIT_FAIL_UNKNOWN_REASON_ERROR_MESSAGE = "Multiple account PublicClientApplication could not be created for unknown reasons";
+
+    /**
+     * AccountMode in configuration is not set to multiple. Cannot initialize multiple account PublicClientApplication.
+     */
+    public static final String MULTIPLE_ACCOUNT_PCA_INIT_FAIL_ACCOUNT_MODE_ERROR_CODE = "multiple_account_pca_init_fail_account_mode";
+    public static final String MULTIPLE_ACCOUNT_PCA_INIT_FAIL_ACCOUNT_MODE_ERROR_MESSAGE = "AccountMode in configuration is not set to multiple. Cannot initialize multiple account PublicClientApplication.";
+
+    /**
+     * AccountMode in configuration is not set to single. Cannot initialize single account PublicClientApplication.
+     */
+    public static final String SINGLE_ACCOUNT_PCA_INIT_FAIL_ACCOUNT_MODE_ERROR_CODE = "single_account_pca_init_fail_account_mode";
+    public static final String SINGLE_ACCOUNT_PCA_INIT_FAIL_ACCOUNT_MODE_ERROR_MESSAGE = "AccountMode in configuration is not set to single. Cannot initialize single account PublicClientApplication.";
+
+    /**
+     * A single account public client application could not be created for unknown reasons.
+     */
+    public static final String SINGLE_ACCOUNT_PCA_INIT_FAIL_UNKNOWN_REASON_ERROR_CODE = "single_account_pca_init_fail_unknown_reason";
+    public static final String SINGLE_ACCOUNT_PCA_INIT_FAIL_UNKNOWN_REASON_ERROR_MESSAGE = "A single account public client application could not be created for unknown reasons.";
+
 }