When upgrading your application to a newer version of 4D and opening it with an older data file for the first time, you may encounter a warning message that states “Logical problems have been detected during the opening of the data file” and “Index on unique field: Table.ID contains duplicate keys”. This issue may arise from improper creation of UUIDs.

First, open the Maintenance & Security Center and verify the records and indexes. If anomalies are detected, do a standard repair to fix any index issues. Then, after reopening the database, if you still encounter the above messages for certain fields, check the values for those fields.

You may see that a UUID field has the same “202020…” (repeating) value for multiple records. This basically indicates that the UUIDs are blank, most likely a result of improper creation. If you see this, you should regenerate the UUIDs.