There is a bug in 5.0.0 around the field definition for the Account Name vardef. See bugs 19293 and 18988 which are symptoms of the same problem.
I will work with the dev team to get this addressed in the next patch. In the meantime, the workaround is the following:
Open the ./modules/Leads/vardefs.php file for editing.
1. Replace the following array: 'account_name' =>
array (
'name' => 'account_name',
'rname' => 'name',
'id_name' => 'account_id',
'vname' => 'LBL_ACCOUNT_NAME',
'join_name'=>'accounts',
'type' => 'relate',
'link' => 'accounts',
'table' => 'accounts',
'isnull' => 'true',
'module' => 'Accounts',
'dbType' => 'varchar',
'len' => '255',
),
with: 'account_name' =>
array (
'name' => 'account_name',
'vname' => 'LBL_ACCOUNT_NAME',
'type' => 'varchar',
'len' => '255',
'unified_search' => true,
'comment' => 'Account name for lead'
),
2. Save the file.
3. Rebuild your module relationships by click on Admin->Repair->Rebuild Relationships. Note: Updated post with this step.
4. Rebuild your SugarCRM cache by going to Admin->Repair->Quick Repair and Rebuild and clicking Repair. Note: Updated post with this step.
5. Refresh your SugarCRM connection by logging out and back in.
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