diff --git a/ui/BankingAndroidApp/src/main/java/net/dankito/banking/ui/android/di/BankingModule.kt b/ui/BankingAndroidApp/src/main/java/net/dankito/banking/ui/android/di/BankingModule.kt
index 31814a40..d598568b 100644
--- a/ui/BankingAndroidApp/src/main/java/net/dankito/banking/ui/android/di/BankingModule.kt
+++ b/ui/BankingAndroidApp/src/main/java/net/dankito/banking/ui/android/di/BankingModule.kt
@@ -62,32 +62,40 @@ class BankingModule(private val applicationContext: Context) {
     @Singleton
     @Named(DataFolderKey)
     fun provideDataFolder(applicationContext: Context) : File {
-        return File(applicationContext.filesDir, "data")
+        return ensureFolderExists(applicationContext.filesDir, "data")
     }
 
     @Provides
     @Singleton
     @Named(DatabaseFolderKey)
     fun provideDatabaseFolder(@Named(DataFolderKey) dataFolder: File) : File {
-        return File(dataFolder, "db")
+        return ensureFolderExists(dataFolder, "db")
     }
 
     @Provides
     @Singleton
     @Named(IndexFolderKey)
     fun provideIndexFolder(@Named(DataFolderKey) dataFolder: File) : File {
-        return File(dataFolder, "index")
+        return ensureFolderExists(dataFolder, "index")
+    }
+
+    private fun ensureFolderExists(parentFolder: File, folderName: String): File {
+        val folder = File(parentFolder, folderName)
+
+        folder.mkdirs()
+
+        return folder
     }
 
 
     @Provides
     @Singleton
     fun provideBankingPresenter(bankingClientCreator: IBankingClientCreator, bankFinder: IBankFinder,
-                                @Named(DatabaseFolderKey) databaseFolder: File, @Named(DataFolderKey) dataFolder: File,
+                                @Named(DataFolderKey) dataFolder: File,
                                 persister: IBankingPersistence, remitteeSearcher: IRemitteeSearcher, bankIconFinder: IBankIconFinder,
                                 textExtractorRegistry: ITextExtractorRegistry, router: IRouter, invoiceDataExtractor: IInvoiceDataExtractor,
                                 serializer: ISerializer, threadPool: IThreadPool) : BankingPresenter {
-        return BankingPresenter(bankingClientCreator, bankFinder, databaseFolder, dataFolder, persister,
+        return BankingPresenter(bankingClientCreator, bankFinder, dataFolder, persister,
             remitteeSearcher, bankIconFinder, textExtractorRegistry, router, invoiceDataExtractor, serializer, threadPool)
     }
 
diff --git a/ui/BankingJavaFxApp/src/main/kotlin/net/dankito/banking/ui/javafx/dialogs/mainwindow/MainWindow.kt b/ui/BankingJavaFxApp/src/main/kotlin/net/dankito/banking/ui/javafx/dialogs/mainwindow/MainWindow.kt
index aa6c2e69..f5cfed2d 100755
--- a/ui/BankingJavaFxApp/src/main/kotlin/net/dankito/banking/ui/javafx/dialogs/mainwindow/MainWindow.kt
+++ b/ui/BankingJavaFxApp/src/main/kotlin/net/dankito/banking/ui/javafx/dialogs/mainwindow/MainWindow.kt
@@ -26,11 +26,11 @@ import java.io.File
 
 class MainWindow : View(messages["application.title"]) {
 
-    private val dataFolder = File("data")
+    private val dataFolder = ensureFolderExists(File("."), "data")
 
-    private val databaseFolder = File(dataFolder, "db")
+    private val databaseFolder = ensureFolderExists(dataFolder, "db")
 
-    private val indexFolder = File(dataFolder, "index")
+    private val indexFolder = ensureFolderExists(dataFolder, "index")
 
     private val tesseractTextExtractor = Tesseract4CommandlineImageTextExtractor(TesseractConfig(listOf(OcrLanguage.English, OcrLanguage.German)))
 
@@ -41,9 +41,9 @@ class MainWindow : View(messages["application.title"]) {
     ))
 
     private val presenter = BankingPresenter(fints4kBankingClientCreator(OkHttpWebClient(), Base64ServiceJava8()),
-        LuceneBankFinder(indexFolder), databaseFolder, dataFolder, LuceneBankingPersistence(indexFolder, databaseFolder),
+        LuceneBankFinder(indexFolder), dataFolder, LuceneBankingPersistence(indexFolder, databaseFolder),
         LuceneRemitteeSearcher(indexFolder), BankIconFinder(), textExtractorRegistry, RouterJavaFx())
-//    private val presenter = BankingPresenter(hbci4jBankingClientCreator(), LuceneBankFinder(indexFolder), databaseFolder,
+//    private val presenter = BankingPresenter(hbci4jBankingClientCreator(), LuceneBankFinder(indexFolder),
 //    dataFolder, LuceneBankingPersistence(indexFolder, databaseFolder), LuceneRemitteeSearcher(indexFolder),
 //    BankIconFinder(), textExtractorRegistry, RouterJavaFx())
 
@@ -68,4 +68,13 @@ class MainWindow : View(messages["application.title"]) {
         }
     }
 
+
+    private fun ensureFolderExists(parentFolder: File, folderName: String): File {
+        val folder = File(parentFolder, folderName)
+
+        folder.mkdirs()
+
+        return folder
+    }
+
 }
\ No newline at end of file
diff --git a/ui/BankingUiCommon/src/main/java/net/dankito/banking/ui/presenter/BankingPresenter.kt b/ui/BankingUiCommon/src/main/java/net/dankito/banking/ui/presenter/BankingPresenter.kt
index 3aadaf45..f075ee78 100644
--- a/ui/BankingUiCommon/src/main/java/net/dankito/banking/ui/presenter/BankingPresenter.kt
+++ b/ui/BankingUiCommon/src/main/java/net/dankito/banking/ui/presenter/BankingPresenter.kt
@@ -46,7 +46,6 @@ import kotlin.collections.ArrayList
 open class BankingPresenter(
     protected val bankingClientCreator: IBankingClientCreator,
     protected val bankFinder: IBankFinder,
-    protected val databaseFolder: File,
     protected val dataFolder: File,
     protected val persister: IBankingPersistence,
     protected val remitteeSearcher: IRemitteeSearcher,
@@ -124,8 +123,6 @@ open class BankingPresenter(
 
     protected open fun readPersistedAccounts() {
         try {
-            databaseFolder.mkdirs()
-
             val deserializedAccounts = persister.readPersistedAccounts()
 
             deserializedAccounts.forEach { account ->
@@ -133,7 +130,7 @@ open class BankingPresenter(
                 val bankInfo = BankInfo(bank.name, bank.bankCode, bank.bic, "", "", "", bank.finTsServerAddress, "FinTS V3.0", null)
 
                 val newClient = bankingClientCreator.createClient(bankInfo, account.customerId, account.password,
-                    databaseFolder, threadPool, callback)
+                    dataFolder, threadPool, callback)
 
                 try {
                     newClient.restoreData()
@@ -161,7 +158,7 @@ open class BankingPresenter(
     // TODO: move BankInfo out of fints4k
     open fun addAccountAsync(bankInfo: BankInfo, customerId: String, pin: String, callback: (AddAccountResponse) -> Unit) {
 
-        val newClient = bankingClientCreator.createClient(bankInfo, customerId, pin, databaseFolder, threadPool, this.callback)
+        val newClient = bankingClientCreator.createClient(bankInfo, customerId, pin, dataFolder, threadPool, this.callback)
 
         val startDate = Date()
 
diff --git a/ui/fints4kBankingClient/src/main/kotlin/net/dankito/banking/fints4kBankingClient.kt b/ui/fints4kBankingClient/src/main/kotlin/net/dankito/banking/fints4kBankingClient.kt
index 4add3f33..f2bdb5a2 100644
--- a/ui/fints4kBankingClient/src/main/kotlin/net/dankito/banking/fints4kBankingClient.kt
+++ b/ui/fints4kBankingClient/src/main/kotlin/net/dankito/banking/fints4kBankingClient.kt
@@ -113,7 +113,7 @@ open class fints4kBankingClient(
     override fun getTransactionsAsync(bankAccount: BankAccount, parameter: GetTransactionsParameter, callback: (GetTransactionsResponse) -> Unit) {
         val account = mapper.findAccountForBankAccount(customer, bankAccount)
 
-        if (account == null) {
+        if (account == null) { // TODO: in this case retrieve data from bank, all data should be re-creatable
             callback(GetTransactionsResponse(bankAccount, false, "Cannot find account for ${bankAccount.identifier}")) // TODO: translate
         }
         else {
@@ -159,14 +159,18 @@ open class fints4kBankingClient(
 
     protected open fun saveData() {
         try {
-            serializer.serializeObject(customer, getFints4kClientDataFile())
+            val clientDataFile = getFints4kClientDataFile()
+
+            clientDataFile.parentFile.mkdirs()
+
+            serializer.serializeObject(customer, clientDataFile)
         } catch (e: Exception) {
             log.error("Could not save customer data for $customer", e)
         }
     }
 
     protected open fun getFints4kClientDataFile(): File {
-        return File(dataFolder, "${bank.bankCode}_${customer.customerId}_$fints4kClientDataFilename")
+        return File(File(dataFolder, "fints4k-client"), "${bank.bankCode}_${customer.customerId}_$fints4kClientDataFilename")
     }
 
 }
\ No newline at end of file
diff --git a/ui/hbci4jBankingClient/src/main/kotlin/net/dankito/banking/hbci4jBankingClient.kt b/ui/hbci4jBankingClient/src/main/kotlin/net/dankito/banking/hbci4jBankingClient.kt
index 272f017a..c8a29d1d 100644
--- a/ui/hbci4jBankingClient/src/main/kotlin/net/dankito/banking/hbci4jBankingClient.kt
+++ b/ui/hbci4jBankingClient/src/main/kotlin/net/dankito/banking/hbci4jBankingClient.kt
@@ -298,8 +298,10 @@ open class hbci4jBankingClient(
         // Die Datei kann problemlos geloescht werden. Sie wird beim naechsten mal automatisch neu erzeugt,
         // wenn der Parameter "client.passport.PinTan.init" den Wert "1" hat (siehe unten).
         // Wir speichern die Datei der Einfachheit halber im aktuellen Verzeichnis.
-        dataFolder.mkdirs()
-        val passportFile = File(dataFolder, "passport_${credentials.bankCode}_${credentials.customerId}.dat")
+        val hbciClientFolder = File(dataFolder, "hbci4j-client")
+        hbciClientFolder.mkdirs()
+
+        val passportFile = File(hbciClientFolder, "passport_${credentials.bankCode}_${credentials.customerId}.dat")
 
         // Wir setzen die Kernel-Parameter zur Laufzeit. Wir koennten sie alternativ
         // auch oben in "props" setzen.