Package &1 might get lost in upgrade. Choose another package.

What causes this issue?

Package <(>&<)>1 is not registered in the Development Object Registry
TADIR.

System Response

Packages which are not registered in this table might get lost in an
upgrade and need to be manually recreated after an upgrade. The Key User
artifacts might not be changeable till the package is recreated.
Usually $-Packages are not registered in TADIR.

How to fix this error?

Choose another local Package. without change recording. Create a package
which starts with "TEST_ " and without change recording.

Procedure for System Administrators

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.