diff --git a/services/dataProcessor.ts b/services/dataProcessor.ts
index 3a0b1c5..0009bca 100644
--- a/services/dataProcessor.ts
+++ b/services/dataProcessor.ts
@@ -270,8 +270,32 @@ const isAllowedCustomer = (customer: string): boolean => {
 
 // --- SALES / SELL OUT MAPPING ---
 
+export const validateSellOutHeaders = (headers: string[]) => {
+    const normHeaders = headers.map(h => String(h).trim().toLowerCase());
+
+    const hasYear = normHeaders.includes('year');
+    const hasTime = normHeaders.includes('month') || normHeaders.includes('week');
+    const hasCustomerRef = normHeaders.includes('customer reference') || normHeaders.includes('asin');
+    const hasEan = normHeaders.includes('ean');
+    const hasUnits = normHeaders.includes('units');
+    const hasAmount = normHeaders.includes('amount_eur') || normHeaders.includes('amount');
+
+    const missing = [];
+    if (!hasYear) missing.push('YEAR');
+    if (!hasTime) missing.push('MONTH or WEEK');
+    if (!hasCustomerRef) missing.push('CUSTOMER REFERENCE');
+    if (!hasEan) missing.push('EAN');
+    if (!hasUnits) missing.push('UNITS');
+    if (!hasAmount) missing.push('AMOUNT_EUR');
+
+    if (missing.length > 0) {
+        throw new Error(`Invalid or missing critical columns in Sell-Out Report. Missing: ${missing.join(', ')}`);
+    }
+};
+
 const mapRowToRecord = (row: any, index: number): SalesRecord => {
-    const customer = getColumnValue(row, ['NEW CUSTOMER', 'Customer', 'Client', 'Account', 'Partner', 'COUNTRY', 'Country', 'Market']) || 'Unknown';
+    // Add exact matches to the front of getColumnValue arrays
+    const customer = getColumnValue(row, ['NEW CUSTOMER', 'COUNTRY', 'Customer', 'Client', 'Account', 'Partner', 'Country', 'Market']) || 'Unknown';
     const yearStr = getColumnValue(row, ['YEAR', 'Year', 'D']);
     // Sanitize year string before parsing (remove commas/dots e.g. "2,023")
     let year = parseInt(yearStr.replace(/[,.]/g, '')) || 0;
@@ -299,11 +323,11 @@ const mapRowToRecord = (row: any, index: number): SalesRecord => {
     ]);
 
     const sku = getColumnValue(row, ['RAW ARTICLE NO.', 'SKU', 'Sku', 'Item No']);
-    const title = getColumnValue(row, ['ARTICLE NAME (Craze)', 'Title', 'TITLE', 'Product Title', 'Article Name', 'ArticleName']);
-    const articleName = getColumnValue(row, ['ARTICLE NAME (Craze)', 'Article Name', 'ArticleName', 'Title']);
+    const title = getColumnValue(row, ['ARTICLE NAME (Customer)', 'ARTICLE NAME (Craze)', 'Title', 'TITLE', 'Product Title', 'Article Name']);
+    const articleName = getColumnValue(row, ['ARTICLE NAME (Craze)', 'ARTICLE NAME (Customer)', 'Article Name', 'ArticleName', 'Title']);
 
     const unitsRaw = getColumnValue(row, ['UNITS', 'Units', 'Quantity', 'Qty']);
-    const sellOutRaw = getColumnValue(row, ['AMOUNT', 'Sell Out', 'SellOut', 'Revenue', 'Sales', 'Turnover']);
+    const sellOutRaw = getColumnValue(row, ['AMOUNT_EUR', 'AMOUNT', 'Sell Out', 'SellOut', 'Revenue', 'Sales', 'Turnover']);
 
     return {
         id: `row-${index}`,
@@ -329,6 +353,12 @@ export const processCSV = (fileOrContent: File | string): Promise<SalesRecord[]>
             skipEmptyLines: true,
             complete: (results: any) => {
                 try {
+                    if (results.meta && results.meta.fields) {
+                        validateSellOutHeaders(results.meta.fields);
+                    } else if (results.data && results.data.length > 0) {
+                        validateSellOutHeaders(Object.keys(results.data[0]));
+                    }
+
                     const data: SalesRecord[] = results.data.map((row: any, index: number) => {
                         return mapRowToRecord(row, index);
                     })
@@ -353,6 +383,10 @@ export const processExcel = async (file: File): Promise<SalesRecord[]> => {
         const worksheet = workbook.Sheets[firstSheetName];
         const jsonData = XLSX.utils.sheet_to_json(worksheet, { defval: "" });
 
+        if (jsonData.length > 0) {
+            validateSellOutHeaders(Object.keys(jsonData[0] as object));
+        }
+
         const data: SalesRecord[] = jsonData.map((row: any, index: number) => {
             return mapRowToRecord(row, index);
         })