diff --git a/app/src/main/java/com/infomaniak/swisstransfer/ui/screen/newtransfer/NewTransferViewModel.kt b/app/src/main/java/com/infomaniak/swisstransfer/ui/screen/newtransfer/NewTransferViewModel.kt
index 011adc82d..f19ab8657 100644
--- a/app/src/main/java/com/infomaniak/swisstransfer/ui/screen/newtransfer/NewTransferViewModel.kt
+++ b/app/src/main/java/com/infomaniak/swisstransfer/ui/screen/newtransfer/NewTransferViewModel.kt
@@ -28,6 +28,8 @@ import com.infomaniak.swisstransfer.ui.components.FileUi
 import com.infomaniak.swisstransfer.ui.screen.newtransfer.TransferFilesManager.PickedFile
 import dagger.hilt.android.lifecycle.HiltViewModel
 import dagger.hilt.android.qualifiers.ApplicationContext
+import io.sentry.Sentry
+import io.sentry.SentryLevel
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.FlowPreview
 import kotlinx.coroutines.channels.Channel
@@ -45,6 +47,11 @@ class NewTransferViewModel @Inject constructor(
     private val savedStateHandle: SavedStateHandle,
 ) : ViewModel() {
 
+    // Importing a file locally can take up time. We can't base the list of already used names on _files because a new import with
+    // the same name could occur while the file is not finished importing yet.
+    // This list needs to mark a name a "taken" as soon as the file is queued to be imported and until the file is removed from
+    // the list of already imported files we listen to in the LazyRow.
+    private val alreadyUsedFileNames = AlreadyUsedFileNamesSet()
     private val _files = MutableStateFlow<List<FileUi>>(emptyList())
     private val files: StateFlow<List<FileUi>> = _files
     @OptIn(FlowPreview::class)
@@ -91,8 +98,9 @@ class NewTransferViewModel @Inject constructor(
 
     fun addFiles(uris: List<Uri>) {
         viewModelScope.launch(Dispatchers.IO) {
-            val alreadyUsedFileNames = buildSet { files.value.forEach { add(it.fileName) } }
-            val newFiles = transferFilesManager.getFiles(uris, alreadyUsedFileNames)
+            val newFiles = transferFilesManager.getFiles(uris, isAlreadyUsed = { alreadyUsedFileNames.contains(it) })
+
+            alreadyUsedFileNames.addAll(newFiles.map { it.fileName })
 
             newFiles.forEach { filesToImport.send(it) }
         }
@@ -100,16 +108,23 @@ class NewTransferViewModel @Inject constructor(
 
     fun removeFileByUid(uid: String) {
         viewModelScope.launch(Dispatchers.IO) {
+            var fileName: String? = null
+
             filesMutationMutex.withLock {
                 val files = _files.value.toMutableList()
 
                 val index = files.indexOfFirst { it.uid == uid }.takeIf { it != -1 } ?: return@withLock
                 val fileToRemove = files.removeAt(index)
+                fileName = fileToRemove.fileName
 
                 runCatching { File(fileToRemove.uri).delete() }
 
                 _files.value = files
             }
+
+            fileName?.let {
+                alreadyUsedFileNames.remove(it)
+            }
         }
     }
 
@@ -126,9 +141,9 @@ class NewTransferViewModel @Inject constructor(
             }
         }
 
-        filesMutationMutex.withLock {
-            _files.value = restoredFileData
-        }
+        alreadyUsedFileNames.addAll(restoredFileData.map { it.fileName })
+
+        filesMutationMutex.withLock { _files.value += restoredFileData }
     }
 
     private fun removeLocalCopyFolder() {
@@ -217,6 +232,15 @@ class NewTransferViewModel @Inject constructor(
         }
     }
 
+    class AlreadyUsedFileNamesSet {
+        private val alreadyUsedFileNames = mutableSetOf<String>()
+        private val mutex = Mutex()
+
+        suspend fun contains(fileName: String): Boolean = mutex.withLock { alreadyUsedFileNames.contains(fileName) }
+        suspend fun addAll(filesNames: List<String>): Boolean = mutex.withLock { alreadyUsedFileNames.addAll(filesNames) }
+        suspend fun remove(filesName: String): Boolean = mutex.withLock { alreadyUsedFileNames.remove(filesName) }
+    }
+
     companion object {
         private const val TAG = "File importation"
         const val LOCAL_COPY_FOLDER = "local_copy_folder"
diff --git a/app/src/main/java/com/infomaniak/swisstransfer/ui/screen/newtransfer/TransferFilesManager.kt b/app/src/main/java/com/infomaniak/swisstransfer/ui/screen/newtransfer/TransferFilesManager.kt
index fb6266e41..e2a1325ed 100644
--- a/app/src/main/java/com/infomaniak/swisstransfer/ui/screen/newtransfer/TransferFilesManager.kt
+++ b/app/src/main/java/com/infomaniak/swisstransfer/ui/screen/newtransfer/TransferFilesManager.kt
@@ -26,20 +26,22 @@ import androidx.core.net.toUri
 import com.infomaniak.swisstransfer.ui.components.FileUi
 import com.infomaniak.swisstransfer.ui.utils.FileNameUtils
 import dagger.hilt.android.qualifiers.ApplicationContext
+import io.sentry.Sentry
 import java.io.File
 import javax.inject.Inject
 import javax.inject.Singleton
 
 @Singleton
 class TransferFilesManager @Inject constructor(@ApplicationContext private val appContext: Context) {
-    fun getFiles(uris: List<Uri>, alreadyUsedFileNames: Set<String>): MutableSet<PickedFile> {
-        val currentUsedFileNames = alreadyUsedFileNames.toMutableSet()
-        val files = mutableSetOf<PickedFile>()
+    suspend fun getFiles(uris: List<Uri>, isAlreadyUsed: suspend (String) -> Boolean): Set<PickedFile> {
+        val currentUsedFileNames = mutableSetOf<String>()
 
-        uris.forEach { uri ->
-            getFile(uri, currentUsedFileNames)?.let { file ->
-                currentUsedFileNames += file.fileName
-                files += file
+        val files = buildSet {
+            uris.forEach { uri ->
+                getFile(uri, isAlreadyUsed = { isAlreadyUsed(it) || currentUsedFileNames.contains(it) })?.let { file ->
+                    currentUsedFileNames += file.fileName
+                    add(file)
+                }
             }
         }
 
@@ -62,12 +64,12 @@ class TransferFilesManager @Inject constructor(@ApplicationContext private val a
         }
     }
 
-    private fun getFile(uri: Uri, alreadyUsedFileNames: Set<String>): PickedFile? {
+    private suspend fun getFile(uri: Uri, isAlreadyUsed: suspend (String) -> Boolean): PickedFile? {
         val contentResolver: ContentResolver = appContext.contentResolver
         val cursor: Cursor? = contentResolver.query(uri, null, null, null, null)
 
         return cursor?.getFileNameAndSize()?.let { (name, size) ->
-            val uniqueName = FileNameUtils.postfixExistingFileNames(name, alreadyUsedFileNames)
+            val uniqueName = FileNameUtils.postfixExistingFileNames(name, isAlreadyUsed)
             PickedFile(uniqueName, size, uri)
         }
     }
diff --git a/app/src/main/java/com/infomaniak/swisstransfer/ui/utils/FileNameUtils.kt b/app/src/main/java/com/infomaniak/swisstransfer/ui/utils/FileNameUtils.kt
index 878b01097..705bde4b0 100644
--- a/app/src/main/java/com/infomaniak/swisstransfer/ui/utils/FileNameUtils.kt
+++ b/app/src/main/java/com/infomaniak/swisstransfer/ui/utils/FileNameUtils.kt
@@ -19,11 +19,11 @@ package com.infomaniak.swisstransfer.ui.utils
 
 object FileNameUtils {
 
-    fun postfixExistingFileNames(fileName: String, existingFileNames: Set<String>): String {
-        return if (fileName in existingFileNames) {
+    suspend fun postfixExistingFileNames(fileName: String, isAlreadyUsed: suspend (String) -> Boolean): String {
+        return if (isAlreadyUsed(fileName)) {
             val postfixedFileName = PostfixedFileName.fromFileName(fileName)
 
-            while (postfixedFileName.fullName() in existingFileNames) {
+            while (isAlreadyUsed(postfixedFileName.fullName())) {
                 postfixedFileName.incrementPostfix()
             }