diff --git a/components/bookkeeping/EditAccountDialog.tsx b/components/bookkeeping/EditAccountDialog.tsx
index 2c5b2159..47121c3f 100644
--- a/components/bookkeeping/EditAccountDialog.tsx
+++ b/components/bookkeeping/EditAccountDialog.tsx
@@ -257,14 +257,24 @@ export function EditAccountDialog({ open, onOpenChange, account, onSaved }: Edit
       })
 
       if (!response.ok) {
-        const data = await response.json()
-        throw new Error(data.error || 'Kunde inte uppdatera kontot')
+        const data = await response.json().catch(() => null)
+        // Keep the dialog open so the user can correct and retry; map the
+        // server error to Swedish like the dimension-rule handlers above.
+        toast({
+          title: 'Kunde inte uppdatera kontot',
+          description: getErrorMessage(data, { locale: 'sv' }),
+          variant: 'destructive',
+        })
+        return
       }
 
       onSaved()
       onOpenChange(false)
     } catch {
-      // Error handled silently: toast is in parent
+      toast({
+        title: 'Kunde inte uppdatera kontot',
+        variant: 'destructive',
+      })
     } finally {
       setIsSaving(false)
     }
diff --git a/components/import/OpeningBalancePeriodStep.tsx b/components/import/OpeningBalancePeriodStep.tsx
index 5a93693f..4e61f55d 100644
--- a/components/import/OpeningBalancePeriodStep.tsx
+++ b/components/import/OpeningBalancePeriodStep.tsx
@@ -44,6 +44,11 @@ export default function OpeningBalancePeriodStep({
     totalDebit = Math.round((totalDebit + row.debit_amount) * 100) / 100
     totalCredit = Math.round((totalCredit + row.credit_amount) * 100) / 100
   }
+  // Compare in whole öre, mirroring the engine's validateBalance: a float
+  // epsilon like (< 0.01) would misclassify exact 1-öre imbalances as
+  // balanced, since e.g. 0.03 - 0.02 evaluates to just under 0.01.
+  const balanceDiff = Math.round((totalDebit - totalCredit) * 100) / 100
+  const isBalanced = Math.round((totalDebit - totalCredit) * 100) === 0
 
   useEffect(() => {
     async function fetchPeriods() {
@@ -83,6 +88,7 @@ export default function OpeningBalancePeriodStep({
     !!selectedPeriodId &&
     !periodIsClosed &&
     !periodIsLocked &&
+    isBalanced &&
     !isLoading
 
   const handleExecute = useCallback(() => {
@@ -160,10 +166,23 @@ export default function OpeningBalancePeriodStep({
               {totalCredit.toLocaleString('sv-SE', { minimumFractionDigits: 2 })} SEK
             </span>
           </div>
-          <div className="flex items-center gap-2 pt-1 border-t text-sm">
-            <CheckCircle2 className="h-4 w-4 text-success" />
-            <span className="text-success font-medium">Balanserar</span>
-          </div>
+          {isBalanced ? (
+            <div className="flex items-center gap-2 pt-1 border-t text-sm">
+              <CheckCircle2 className="h-4 w-4 text-success" />
+              <span className="text-success font-medium">Balanserar</span>
+            </div>
+          ) : (
+            <div className="flex items-center gap-2 pt-1 border-t text-sm">
+              <AlertCircle className="h-4 w-4 text-destructive shrink-0" />
+              <span className="text-destructive font-medium">
+                Balanserar inte (differens{' '}
+                <span className="tabular-nums">
+                  {balanceDiff.toLocaleString('sv-SE', { minimumFractionDigits: 2 })}
+                </span>{' '}
+                SEK)
+              </span>
+            </div>
+          )}
         </div>
 
         {/* Error */}
diff --git a/components/supplier-invoices/NewSupplierInvoiceForm.tsx b/components/supplier-invoices/NewSupplierInvoiceForm.tsx
index d3118655..47cd91d3 100644
--- a/components/supplier-invoices/NewSupplierInvoiceForm.tsx
+++ b/components/supplier-invoices/NewSupplierInvoiceForm.tsx
@@ -1059,6 +1059,26 @@ export default function NewSupplierInvoiceForm({
       })
       return
     }
+    // Only 25/12/6/0 % are legal Swedish VAT rates (ML 2023:200). The free-text
+    // VatRateCell clamps to [0, 100] but accepts anything in between, so block
+    // illegal rates here. Reverse-charge invoices skip this: their line vat_rate
+    // is forced to 0 and RcRateSelect already restricts the self-assessed rate.
+    if (!data.reverse_charge) {
+      const rowWithIllegalRate = data.items.findIndex(
+        (item) => !VAT_RATE_PRESETS.includes(item.vat_rate),
+      )
+      if (rowWithIllegalRate !== -1) {
+        toast({
+          title: t('illegal_vat_rate_title'),
+          description: t('illegal_vat_rate_description', {
+            row: rowWithIllegalRate + 1,
+            rate: rateToPctString(data.items[rowWithIllegalRate].vat_rate),
+          }),
+          variant: 'destructive',
+        })
+        return
+      }
+    }
     // A row with an open periodisering panel must carry a complete period of
     // at least two calendar months before the invoice can be booked.
     const invalidAccrual = canUseAccrual && data.items.some((item) => {
diff --git a/messages/en.json b/messages/en.json
index bf7bd21b..c78d6b85 100644
--- a/messages/en.json
+++ b/messages/en.json
@@ -2889,6 +2889,8 @@
     "invoice_number_missing_description": "Enter the supplier's invoice number.",
     "account_missing_title": "Account missing",
     "account_missing_description": "Select an expense account for line {row}.",
+    "illegal_vat_rate_title": "Invalid VAT rate",
+    "illegal_vat_rate_description": "Line {row} has VAT rate {rate} %. The legal Swedish VAT rates are 25, 12, 6 or 0 %.",
     "expense_registered_title": "Expense registered",
     "invoice_registered_title": "Invoice registered",
     "arrival_number_label": "Arrival number: {number}",
diff --git a/messages/sv.json b/messages/sv.json
index a498224e..c091b444 100644
--- a/messages/sv.json
+++ b/messages/sv.json
@@ -2889,6 +2889,8 @@
     "invoice_number_missing_description": "Ange leverantörens fakturanummer.",
     "account_missing_title": "Konto saknas",
     "account_missing_description": "Välj ett bokföringskonto för rad {row}.",
+    "illegal_vat_rate_title": "Ogiltig momssats",
+    "illegal_vat_rate_description": "Rad {row} har momssats {rate} %. Tillåtna momssatser är 25, 12, 6 eller 0 %.",
     "expense_registered_title": "Utlägg registrerat",
     "invoice_registered_title": "Faktura registrerad",
     "arrival_number_label": "Ankomstnummer: {number}",