diff --git a/amethyst/src/main/java/com/vitorpamplona/amethyst/ui/actions/NewPostViewModel.kt b/amethyst/src/main/java/com/vitorpamplona/amethyst/ui/actions/NewPostViewModel.kt
index 1bd8df1da..8491b4ae1 100644
--- a/amethyst/src/main/java/com/vitorpamplona/amethyst/ui/actions/NewPostViewModel.kt
+++ b/amethyst/src/main/java/com/vitorpamplona/amethyst/ui/actions/NewPostViewModel.kt
@@ -222,7 +222,10 @@ open class NewPostViewModel : ViewModel() {
                 if (replyNote.event !is CommunityDefinitionEvent) {
                     replyNote.author?.let { replyUser ->
                         val currentMentions =
-                            (replyNote.event as? TextNoteEvent)?.mentions()?.map { LocalCache.getOrCreateUser(it) }
+                            (replyNote.event as? TextNoteEvent)
+                                ?.mentions()
+                                ?.filter { it.isNotEmpty() }
+                                ?.map { LocalCache.getOrCreateUser(it) }
                                 ?: emptyList()
 
                         if (currentMentions.contains(replyUser)) {
diff --git a/amethyst/src/test/java/com/vitorpamplona/amethyst/ui/actions/NewPostViewModelTest.kt b/amethyst/src/test/java/com/vitorpamplona/amethyst/ui/actions/NewPostViewModelTest.kt
new file mode 100644
index 000000000..8db0d9fde
--- /dev/null
+++ b/amethyst/src/test/java/com/vitorpamplona/amethyst/ui/actions/NewPostViewModelTest.kt
@@ -0,0 +1,125 @@
+/**
+ * Copyright (c) 2024 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.ui.actions
+
+import com.vitorpamplona.amethyst.model.Account
+import com.vitorpamplona.amethyst.model.LocalCache
+import com.vitorpamplona.amethyst.model.Note
+import com.vitorpamplona.amethyst.model.User
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
+import com.vitorpamplona.quartz.encoders.HexKey
+import com.vitorpamplona.quartz.events.TextNoteEvent
+import io.mockk.MockKAnnotations
+import io.mockk.every
+import io.mockk.impl.annotations.MockK
+import io.mockk.mockk
+import io.mockk.mockkObject
+import io.mockk.unmockkAll
+import io.mockk.verify
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.test.runTest
+import org.junit.After
+import org.junit.Before
+import org.junit.Test
+
+@ExperimentalCoroutinesApi
+class NewPostViewModelTest {
+    @MockK
+    lateinit var accountViewModel: AccountViewModel
+
+    @MockK(relaxed = true)
+    lateinit var replyingTo: Note
+
+    private lateinit var newPostViewModelUnderTest: NewPostViewModel
+
+    @Before
+    fun setup() {
+        mockkObject(LocalCache)
+        every { LocalCache.getOrCreateUser(any<HexKey>()) } returns mockk<User>()
+        newPostViewModelUnderTest = NewPostViewModel()
+        MockKAnnotations.init(this)
+    }
+
+    @After
+    fun tearDown() {
+        unmockkAll()
+    }
+
+    @Test
+    fun `test load with mentions`() =
+        runTest {
+            // Arrange: Setup with non empty mentions
+            every { accountViewModel.account } returns mockk<Account>()
+
+            val textNoteEvent = mockk<TextNoteEvent>(relaxed = true)
+            every { textNoteEvent.mentions() } returns listOf("user1", "user2")
+            every { replyingTo.event } returns textNoteEvent
+
+            every { accountViewModel.userProfile() } returns mockk<User>(relaxed = true)
+
+            // Act: Call load with mentions
+            newPostViewModelUnderTest.load(accountViewModel, replyingTo, quote = null, fork = null, version = null, draft = null)
+
+            // Assert
+            // Two mentions should call LocalCache.getOrCreateUser twice
+            verify(exactly = 2) { LocalCache.getOrCreateUser(any()) }
+        }
+
+    @Test
+    fun `test load with zero mentions`() =
+        runTest {
+            // Arrange: Setup Note with zero mentions
+            every { accountViewModel.account } returns mockk<Account>()
+
+            val textNoteEvent = mockk<TextNoteEvent>(relaxed = true)
+            every { textNoteEvent.mentions() } returns emptyList()
+            every { replyingTo.event } returns textNoteEvent
+
+            every { accountViewModel.userProfile() } returns mockk<User>(relaxed = true)
+
+            // Act: Call load with empty mentions
+            newPostViewModelUnderTest.load(accountViewModel, replyingTo, quote = null, fork = null, version = null, draft = null)
+
+            // Assert
+            // With no mentions LocalCache.getOrCreateUser should not be called
+            verify(exactly = 0) { LocalCache.getOrCreateUser(any()) }
+        }
+
+    @Test
+    fun `test load with empty mentions`() =
+        runTest {
+            // Arrange: Setup empty mentions
+            every { accountViewModel.account } returns mockk<Account>()
+
+            val textNoteEvent = mockk<TextNoteEvent>(relaxed = true)
+            every { textNoteEvent.mentions() } returns listOf("")
+            every { replyingTo.event } returns textNoteEvent
+
+            every { accountViewModel.userProfile() } returns mockk<User>(relaxed = true)
+
+            // Act: Call load with empty mentions
+            newPostViewModelUnderTest.load(accountViewModel, replyingTo, quote = null, fork = null, version = null, draft = null)
+
+            // Assert
+            // Verify LocalCache.getOrCreateUser(it) is not called with empty hex, it will crash the app
+            verify(exactly = 0) { LocalCache.getOrCreateUser(any()) }
+        }
+}