Data Loaders have a built in record lock prevention feature. If a record is locked by another user during an upload, Data Loaders will stop processing the batch of records, highlight the locked record, and notify the user that this record is locked by another user.
The first user can then decide to either delete the locked record and re-upload the file or try to upload the file later when the locked record becomes available. It is possible to customize Data Loaders to provide users with the name of the user who has locked a record.
We have dozens of Data Loader modules for every major QAD data management process: