diff --git a/app/api/mail/send/route.ts b/app/api/mail/send/route.ts
index 71f816d..a068aa5 100644
--- a/app/api/mail/send/route.ts
+++ b/app/api/mail/send/route.ts
@@ -9,6 +9,9 @@ interface StoredCredentials {
   port: number;
 }
 
+// Maximum attachment size in bytes (10MB)
+const MAX_ATTACHMENT_SIZE = 10 * 1024 * 1024;
+
 function getStoredCredentials(): StoredCredentials | null {
   const cookieStore = cookies();
   const credentialsCookie = cookieStore.get('imap_credentials');
@@ -40,6 +43,28 @@ export async function POST(request: Request) {
 
     const { to, cc, bcc, subject, body, attachments } = await request.json();
 
+    // Check attachment sizes
+    if (attachments?.length) {
+      const oversizedAttachments = attachments.filter((attachment: any) => {
+        // Calculate size from base64 content
+        const size = Math.ceil((attachment.content.length * 3) / 4);
+        return size > MAX_ATTACHMENT_SIZE;
+      });
+
+      if (oversizedAttachments.length > 0) {
+        return NextResponse.json(
+          { 
+            error: 'Attachment size limit exceeded',
+            details: {
+              maxSize: MAX_ATTACHMENT_SIZE,
+              oversizedFiles: oversizedAttachments.map((a: any) => a.name)
+            }
+          },
+          { status: 400 }
+        );
+      }
+    }
+
     // Create a transporter using SMTP with the same credentials
     // Use port 465 for SMTP (Infomaniak's SMTP port)
     const transporter = createTransport({
diff --git a/app/mail/page.tsx b/app/mail/page.tsx
index 9b6d1b8..edd3c48 100644
--- a/app/mail/page.tsx
+++ b/app/mail/page.tsx
@@ -1184,8 +1184,15 @@ export default function MailPage() {
     if (!e.target.files) return;
     
     const newAttachments: Attachment[] = [];
+    const MAX_FILE_SIZE = 10 * 1024 * 1024; // 10MB in bytes
+    const oversizedFiles: string[] = [];
     
     for (const file of e.target.files) {
+      if (file.size > MAX_FILE_SIZE) {
+        oversizedFiles.push(file.name);
+        continue;
+      }
+
       try {
         // Read file as base64
         const base64Content = await new Promise<string>((resolve) => {
@@ -1208,7 +1215,13 @@ export default function MailPage() {
       }
     }
 
-    setAttachments([...attachments, ...newAttachments]);
+    if (oversizedFiles.length > 0) {
+      alert(`The following files exceed the 10MB size limit and were not attached:\n${oversizedFiles.join('\n')}`);
+    }
+
+    if (newAttachments.length > 0) {
+      setAttachments([...attachments, ...newAttachments]);
+    }
   };
 
   // Add handleSend function for email composition
@@ -1230,27 +1243,29 @@ export default function MailPage() {
           bcc: composeBcc,
           subject: composeSubject,
           body: composeBody,
-          attachments: attachments
+          attachments: attachments,
         }),
       });
 
+      const data = await response.json();
+
       if (!response.ok) {
-        throw new Error('Failed to send email');
+        if (data.error === 'Attachment size limit exceeded') {
+          alert(`Error: ${data.error}\nThe following files are too large:\n${data.details.oversizedFiles.join('\n')}`);
+        } else {
+          alert(`Error sending email: ${data.error}`);
+        }
+        return;
       }
 
       // Clear compose form and close modal
-      setShowCompose(false);
       setComposeTo('');
       setComposeCc('');
       setComposeBcc('');
       setComposeSubject('');
       setComposeBody('');
       setAttachments([]);
-      setShowCc(false);
-      setShowBcc(false);
-
-      // Reload emails to show sent email
-      loadEmails();
+      setShowCompose(false);
     } catch (error) {
       console.error('Error sending email:', error);
       alert('Failed to send email. Please try again.');
@@ -1347,7 +1362,7 @@ export default function MailPage() {
             .replace(/<p[^>]*>/gi, '\n')
             .replace(/<\/p>/gi, '')
             .replace(/<[^>]+>/g, '')
-            .replace(/&nbsp;|&zwnj;|&raquo;|&laquo;|&gt;|&lt;|&amp;/g, match => {
+            .replace(/&nbsp;|&zwnj;|&raquo;|&laquo;|&gt;/g, match => {
               switch (match) {
                 case '&nbsp;': return ' ';
                 case '&zwnj;': return '';