Hi, In order to Delete an invoice(which is validated), you have to edit the unlink method of account_invoice.

1) At first you have to install a account_cancel module.

2) Allow Cancelling Entries of corresponding journals.

3) After that you will have to cancel posted journal entries of that invoice.

4) then you are able to cancel the invoice. now you are ready to delete this invoice.

Go to Addons>>account module, open account_invoice.py file. find the unlink method which is same as:

def unlink(self, cr, uid, ids, context=None):
    if context is None:
        context = {}
    invoices = self.read(cr, uid, ids, ['state','internal_number'], context=context)
    unlink_ids = []
    for t in invoices:
        if t['state'] in ('draft', 'cancel') and t['internal_number']== False:
            unlink_ids.append(t['id'])
        else:
            raise osv.except_osv(_('Invalid Action!'), _('You can not delete an invoice which is not cancelled. You should refund it instead.'))
    osv.osv.unlink(self, cr, uid, unlink_ids, context=context)
    return True

Just remove "and t['internal_number']== False" from if statement or change it to "and t['internal_number']== True", and save it. after doing it you have to restart the openerp server. Now go to admin and delete the canceled invoice, it will work perfectly.

There is also an another trick, which will work every time.

In account_invoice.py in the 'action_cancel' method

self.write(cr, uid, ids, {'state':'cancel', 'move_id':False})

just replace this code with below one:

self.write(cr, uid, ids, {'state':'cancel', 'internal_number':False ,'move_id':False})

If the Invoice has not been paid, you can CANCEL it.

Only do this if you are sure the Invoice has not been sent to your Customer/Supplier.

How to delete an invoice after validation? On Odoo V10 (version 10)

1- To install a account_cancel module.

2- Go to file:

sudo nano /usr/lib/python2.7/dist-packages/odoo/addons/account/models/account_invoice.py

or:

addons/account/models/account_invoice.py

Note: I recommend create a save to file before.

2- Comment the function unlink like:    

    @api.multi        
    def unlink(self):
        #for invoice in self:
        #    #if invoice.state not in ('draft', 'cancel'):
        #    #    raise UserError(_('You cannot delete an invoice which is not draft or cancelled. You should refund it instead.'))        
        #    #elif invoice.move_name:
        #    #    raise UserError(_('You cannot delete an invoice after it has been validated (and received a number). You can set it back to "Draft" state and modify its content, then re-confirm it.')) 
        return super(AccountInvoice, self).unlink()

3- Go to View and Remove the Invoce.

I hope help you!

Jose Carlos Ramos Carmenates

Hi,

use a refund for that.

bye

 Here is my response to the same issue with a few steps to make this possible., without install any module, or addon

https://www.odoo.com/forum/help-1/question/how-to-delete-a-validated-invoice-in-the-online-odoo-version-125118

You can set the sales journal to allow canceling entries. by going to Configuration > Journals. Then you can cancel the invoice to remove any journal entries and the invoice will appear grayed out in your list. OR you can refund it if thats more applicable to the particular situation.

However, you shouldn't be able to delete the record completely from OpenERP, once it has been validated. Full deletion would not be fantastic accounting practice as there wouldn't be any traceability :)

Hope that helps.

Hello,

I stuck at step 4 ... In my installation (openerp 7, python 2.6, centos) following fragment of account_invoice.py code is little different, eg:

def unlink(self, cr, uid, ids, context=None):
         if context is None:
             context = {}
         invoices = self.read(cr, uid, ids, ['state','internal_number'], context=context)
         unlink_ids = []

         for t in invoices:
             if t['state'] not in ('draft', 'cancel'):
                 raise openerp.exceptions.Warning(_('You cannot delete an invoice which is not draft or cancelled. You should refund it instead.'))
             elif t['internal_number']:
                 raise openerp.exceptions.Warning(_('You cannot delete an invoice after it has been validated (and received a number).  You can set it back to "Draft" state and modify its content, the        n re-confirm it.'))
             else:
                 unlink_ids.append(t['id'])

         osv.osv.unlink(self, cr, uid, unlink_ids, context=context)
         return True

     def onchange_partner_id(self, cr, uid, ids, type, partner_id,\
             date_invoice=False, payment_term=False, partner_bank_id=False, company_id=False):
         partner_payment_term = False
         acc_id = False
         bank_id = False
         fiscal_position = False

There is no such thing like: t['internal_number']== False. I tried delete this line, modify content sth, but installation just hangs.

Also, I can modify account_invoice.py content using second method, openerp working, but with no effect (invoice still cant be deleted). In log i have following output:

Traceback (most recent call last): File "/usr/lib/python2.6/site-packages/openerp-7.0_20130908_231053-py2.6.egg/openerp/osv/osv.py", line 131, in wrapper return f(self, dbname, args, *kwargs) File "/usr/lib/python2.6/site-packages/openerp-7.0_20130908_231053-py2.6.egg/openerp/osv/osv.py", line 197, in execute res = self.execute_cr(cr, uid, obj, method, args, *kw) File "/usr/lib/python2.6/site-packages/openerp-7.0_20130908_231053-py2.6.egg/openerp/osv/osv.py", line 185, in execute_cr return getattr(object, method)(cr, uid, args, *kw) File "/usr/lib/python2.6/site-packages/openerp-7.0_20130908_231053-py2.6.egg/openerp/addons/sale/sale.py", line 1012, in unlink return super(account_invoice, self).unlink(cr, uid, ids, context=context) File "/usr/lib/python2.6/site-packages/openerp-7.0_20130908_231053-py2.6.egg/openerp/addons/account/account_invoice.py", line 474, in unlink

Any ideas will be welcomed :)

2) Allow Cancelling Entries of corresponding journals.

Hi, I am stuck on step 2. I have installed account_cancel module.

Yet, in settings-->>accounting-->>configuration -- I do not have any check options relating to journals. I have unistalled and re-installed account_cancel module, updated it, looked at the technical features tab etc and nothing.

It simply isn't showing up under settings. I can't select "cancel entries of corresponding journals" because I cannot find it!

any advice/ thoughts please? Very much appreciated.

Hello everyone here is my fastest solution: 

1. Install account_cancel module

2. Cancel invoice

3. Set invoice to draft

4. Go to the database and find table account_invoice and set move_name = null

5. Go back to invoices and delete an invoice

6. Change counter in a journal back if you want