FLEXnet/FLEXlm: Error [1.5.-124] attempting to return a borrowed license early

Issue

The following error message is displayed when attempting to return a borrowed license from a client workstation:
License Return Error – Your license cannot be returned. For more information, contact your system administrator. Note: you can still use your borrowed license until (midnight): <Date>. Error: [1.5.-124]

Solution

This error usually indicates that the client and/or license manager have changed since the license was originally borrowed. For example, attempting to return a borrowed license early may cause this problem for that very reason. However, the following procedures will often resolve the error.
Method 1 – Wait out the borrow period
Depending on the extent of the time on which your license is borrowed and how urgently it needs to be returned to the network pool, simply waiting out the remainder of the borrow period is a simple and effective solution. After all, the license will be automatically returned at the end of this period. A viable option for Network administrators is implementing an Options file to restrict the maximum borrow period or limit those who can borrow licenses, reducing the impact of future borrowing problems. OpenLM provides full interface to all the license borrowing related options available in FLEXnet.

Method 2 – Reborrow the license and then return it
This method essentially consists of erasing knowledge of the borrowed license from the client machine, borrowing it again, and then attempting to return it. Note: This procedure resets all borrowed licenses for this user/computer.

1. On the client computer, log in as the user who borrowed the license.
2. On the Start menu (Windows), click Run (Windows 2000/XP) or StartSearch (Windows Vista).
3. Enter regedit, and then click OK.
4. In the Registry Editor, navigate to the following registry key:
• HKEY_CURRENT_USERSoftwareFLEXlm License ManagerBorrow
5. In the Registry Editor, on the File menu, click Export to create a backup of this key.
6. Delete this registry key.
7. Close the Registry Editor.
8. Borrow the license again for the product(s) and version(s) that you could not return.
9. Return the license(s) for each product.