VirtueMart 2.x.x is a completely new shopping cart system which is not compatible with VirtueMart 1.x.x!
Please read the information available in the VirtueMart forum at the link below first:
Migrating VM1 to VM2 with provided packages¶
The order of steps in short:
1. First uninstall all old vm extensions.
2. Just install VM2 as upgrade over VM1 (just use the joomla install view)
4. Make your life easy and use the sample data.
3. Copy your vm1 images into the desired folders (you can also adjust the paths in the config to your old vm folders)
4. Go to Migration and Tools in the backend.
5. Use on the second tab the option all and fire the button.
Very important! Depending on your shops size and your server, the migration process may stop. Then just repeat the migration. The migrator is resuming. This means the migrator stores the already ported data and does not import it twice. In theory you can press the buttons as often as you want.
Be sure that you disabled/uninstalled ALL Vm1.1 related plugins and modules.
Just install VM2 over VM1. Dont uninstall VM1, or you would lose your data. The VM2 installer package is also suitable for upgrading. You need not to fear that your database data gets lost. Of course you should have a backup for emergency problems (you may use akeeba backup).
The migrator does not look on plugins, components or modules. So when you have VM1 extensions, you need to check first if an update for this extension is available.
The best order is already used, when you use the option "all". It is just using all options from left to right. The sequel is media, shoppergroups, users, categories, manufacturerCategories, manufacturers, products, orders.
When you get an error while the migration process, nothing is lost. The tools provide buttons for this. Use the "Remove Virtuemart Tables" to delete all user generated data, after that use one of the migrationtools. The migrator is able to handle data which is already there. Because the migrator does not just copy the db data. The migrator gets the information of the old "_vm_" tables and adds them to VM2 using the VM2 models into the tables with prefix "_virtuemart_". This means for example, when your old products used the ids from 100-500, they will have the ids 1-401 in VM2.
The button "Reset all tables and install sampledata" deletes ALL "_virtuemart_" tables and reinstalls all tables and inserts the sample data. This is like a completly new install regarding the SQL. The button "Restore System Defaults" is kind of the opposite of "Remove Virtuemart Tables". It reinstalles all VM2 information, which is normally not user generated, this are states, countries, currency, orderstatus, adminmenu,...
When you have trouble and getting strange errors, please check if your toolbar.virtuemart.php is deleted.
Sometimes the related products are missing, or some other customfields. Then you need a high php execution time and you may try the scripts provided in beta (they are not false prove and not so error tolerante then the main function). you may join the forum for enhancement here http://forum.virtuemart.net/index.php?topic=102083.msg392238#msg392238