Error: "The generated script can produce data loss. Number of warnings: 2. Do you want to proceed (4325637)

There are two Oracle physical models corresponding to two consecutive versions of the same database.

The purpose is to transfer all the indexes' definitions from the old model into the new one using the model merge functionality in Toad Data Modeler.

While the application starts processing, it displays the following message "The generated script can produce data loss. Number of warnings : 2. Do you want to proceed with script generation without check ?".

If the "yes" button is clicked, the merge stops and no index is transfered to the new model.
If the "no" button is clicked, an exclamation mark appears next to the  two tables.

After unchecking them to put them out of the scope of the merge, and after clicking the "Execute" button, it brings an "out of memory" error message.

In the old model, e.g.  'V1':
1.  Remove the user/schema from objects via Model menu | Schema Owner Assignment - in the Schema... Assignment dialog, select None in the first box and press Execute.
2. Then delete all model tablespaces from the  Model Explorer.
3. Open Convertor - old model 'V1' as 'Model1', new model 'V2 Oracle' as 'Model2'.
4. Click the Settings tab and clear all checkboxes.
5. Now select the Entities item (only this item, do not select its sub-items) and Indexes item with all its sub-items.
6. Click the Models tab again.
7. See the icons next to the 'Model2' box. There are three icons available. By default, the first icon is selected, however this stands for alter script generation.
8. Enable the second or third icon for the model merge. (second icon = 'Model2' will be refreshed, third icon = 'Model1' and 'Model2' will be merged to a new model).
9. Click the 'Expand All Nodes' icon.   Differences will be shown. Only basic differences between entities and all differences between indexes should be shown.
10. Click 'Execute'  to see the result.