diff --git a/CHANGELOG.md b/CHANGELOG.md
index d9a3ec583b..50cc80581a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,10 @@
 - #2045 add action to input on-screen keyboard enter/send button.
 - #2106 disable the keyboard auto-switching setting when manually switching the keyboard in the Key Mapper homescreen menu.
 
+## Fixed
+
+- #2091 show an error on the "open device assistant" action when no device assistant is installed.
+
 ## [4.0.5](https://github.com/sds100/KeyMapper/releases/tag/v4.0.5)
 
 #### 26 February 2026
diff --git a/base/src/main/java/io/github/sds100/keymapper/base/actions/ActionErrorSnapshot.kt b/base/src/main/java/io/github/sds100/keymapper/base/actions/ActionErrorSnapshot.kt
index a79591be43..9cf7a00748 100644
--- a/base/src/main/java/io/github/sds100/keymapper/base/actions/ActionErrorSnapshot.kt
+++ b/base/src/main/java/io/github/sds100/keymapper/base/actions/ActionErrorSnapshot.kt
@@ -8,6 +8,7 @@ import io.github.sds100.keymapper.common.BuildConfigProvider
 import io.github.sds100.keymapper.common.models.ShellExecutionMode
 import io.github.sds100.keymapper.common.utils.KMError
 import io.github.sds100.keymapper.common.utils.firstBlocking
+import io.github.sds100.keymapper.common.utils.isSuccess
 import io.github.sds100.keymapper.common.utils.onFailure
 import io.github.sds100.keymapper.common.utils.onSuccess
 import io.github.sds100.keymapper.common.utils.valueOrNull
@@ -53,6 +54,9 @@ class LazyActionErrorSnapshot(
     private val isCompatibleImeEnabled by lazy { keyMapperImeHelper.isCompatibleImeEnabled() }
     private val isCompatibleImeChosen by lazy { keyMapperImeHelper.isCompatibleImeChosen() }
     private val isVoiceAssistantInstalled by lazy { packageManager.isVoiceAssistantInstalled() }
+    private val isDeviceAssistantInstalled by lazy {
+        packageManager.getDeviceAssistantPackage().isSuccess
+    }
     private val grantedPermissions: MutableMap<Permission, Boolean> = mutableMapOf()
     private val flashLenses by lazy {
         buildSet {
@@ -190,6 +194,12 @@ class LazyActionErrorSnapshot(
                 }
             }
 
+            is ActionData.DeviceAssistant -> {
+                if (!isDeviceAssistantInstalled) {
+                    return KMError.NoDeviceAssistant
+                }
+            }
+
             is ActionData.Flashlight ->
                 if (!flashLenses.contains(action.lens)) {
                     return when (action.lens) {
diff --git a/base/src/test/java/io/github/sds100/keymapper/base/actions/GetActionErrorUseCaseTest.kt b/base/src/test/java/io/github/sds100/keymapper/base/actions/GetActionErrorUseCaseTest.kt
index f3f233625b..f1a978b026 100644
--- a/base/src/test/java/io/github/sds100/keymapper/base/actions/GetActionErrorUseCaseTest.kt
+++ b/base/src/test/java/io/github/sds100/keymapper/base/actions/GetActionErrorUseCaseTest.kt
@@ -5,10 +5,12 @@ import io.github.sds100.keymapper.base.repositories.FakePreferenceRepository
 import io.github.sds100.keymapper.base.system.inputmethod.FakeInputMethodAdapter
 import io.github.sds100.keymapper.base.utils.TestBuildConfigProvider
 import io.github.sds100.keymapper.common.utils.KMError
+import io.github.sds100.keymapper.common.utils.Success
 import io.github.sds100.keymapper.data.Keys
 import io.github.sds100.keymapper.sysbridge.manager.SystemBridgeConnectionManager
 import io.github.sds100.keymapper.sysbridge.manager.SystemBridgeConnectionState
 import io.github.sds100.keymapper.sysbridge.utils.SystemBridgeError
+import io.github.sds100.keymapper.system.apps.PackageManagerAdapter
 import io.github.sds100.keymapper.system.inputmethod.ImeInfo
 import io.github.sds100.keymapper.system.permissions.Permission
 import io.github.sds100.keymapper.system.permissions.PermissionAdapter
@@ -59,6 +61,7 @@ class GetActionErrorUseCaseTest {
     private lateinit var mockPermissionAdapter: PermissionAdapter
     private lateinit var fakePreferenceRepository: FakePreferenceRepository
     private lateinit var mockSystemBridgeConnectionManager: SystemBridgeConnectionManager
+    private lateinit var mockPackageManagerAdapter: PackageManagerAdapter
 
     @Before
     fun init() {
@@ -66,9 +69,10 @@ class GetActionErrorUseCaseTest {
         mockPermissionAdapter = mock()
         fakePreferenceRepository = FakePreferenceRepository()
         mockSystemBridgeConnectionManager = mock()
+        mockPackageManagerAdapter = mock()
 
         useCase = GetActionErrorUseCaseImpl(
-            packageManagerAdapter = mock(),
+            packageManagerAdapter = mockPackageManagerAdapter,
             inputMethodAdapter = fakeInputMethodAdapter,
             switchImeInterface = mock(),
             permissionAdapter = mockPermissionAdapter,
@@ -300,4 +304,32 @@ class GetActionErrorUseCaseTest {
 
             assertThat(errors[0], `is`(KMError.KeyEventActionError(SystemBridgeError.Disconnected)))
         }
+
+    @Test
+    fun `show an error for device assistant action when no device assistant is installed`() =
+        testScope.runTest {
+            whenever(
+                mockPackageManagerAdapter.getDeviceAssistantPackage(),
+            ).thenReturn(KMError.NoDeviceAssistant)
+
+            val action = ActionData.DeviceAssistant
+
+            val errors = useCase.actionErrorSnapshot.first().getErrors(listOf(action))
+
+            assertThat(errors[action], `is`(KMError.NoDeviceAssistant))
+        }
+
+    @Test
+    fun `do not show an error for device assistant action when a device assistant is installed`() =
+        testScope.runTest {
+            whenever(
+                mockPackageManagerAdapter.getDeviceAssistantPackage(),
+            ).thenReturn(Success("com.google.android.googlequicksearchbox"))
+
+            val action = ActionData.DeviceAssistant
+
+            val errors = useCase.actionErrorSnapshot.first().getErrors(listOf(action))
+
+            assertThat(errors[action], nullValue())
+        }
 }