diff --git a/app/Import/Converter/Amount.php b/app/Import/Converter/Amount.php
index 1177b86a2e..bf1f23fdf9 100644
--- a/app/Import/Converter/Amount.php
+++ b/app/Import/Converter/Amount.php
@@ -36,6 +36,10 @@ class Amount implements ConverterInterface
      */
     public function convert($value): string
     {
+        if(is_null($value)) {
+            return '0';
+        }
+        $value = strval($value);
         Log::debug(sprintf('Start with amount "%s"', $value));
         $len             = strlen($value);
         $decimalPosition = $len - 3;
diff --git a/app/Import/Storage/ImportStorage.php b/app/Import/Storage/ImportStorage.php
index ee3f086790..f0d9e3f9f4 100644
--- a/app/Import/Storage/ImportStorage.php
+++ b/app/Import/Storage/ImportStorage.php
@@ -39,7 +39,7 @@ class ImportStorage
     /** @var string */
     private $dateFormat = 'Ymd'; // yes, hard coded
     /** @var  ImportJob */
-    private $job;
+    protected $job;
     /** @var Collection */
     private $objects;
     /** @var Collection */
diff --git a/app/Repositories/Journal/JournalRepository.php b/app/Repositories/Journal/JournalRepository.php
index 58bde274d0..84e964735c 100644
--- a/app/Repositories/Journal/JournalRepository.php
+++ b/app/Repositories/Journal/JournalRepository.php
@@ -196,7 +196,7 @@ class JournalRepository implements JournalRepositoryInterface
         $journal->save();
 
         // store stuff:
-        $this->storeCategoryWithJournal($journal, $data['category']);
+        $this->storeCategoryWithJournal($journal, strval($data['category']));
         $this->storeBudgetWithJournal($journal, $data['budget_id']);
 
         // store two transactions:
@@ -271,7 +271,7 @@ class JournalRepository implements JournalRepositoryInterface
         $journal->categories()->detach();
         $journal->budgets()->detach();
 
-        $this->storeCategoryWithJournal($journal, $data['category']);
+        $this->storeCategoryWithJournal($journal, strval($data['category']));
         $this->storeBudgetWithJournal($journal, $data['budget_id']);
 
         // negative because source loses money.