There is a known issue that William commented on about 2025r3 and using Tahoe on an external disk. The report describes behavior exactly as OP does.
I can’t find the ticket now, but William’s response was less than satisfactory to the effect of “we don’t have an interest in fixing this.”
That answer is sad, and is also used for other things I’d really like to gather an interest from Xojo rather than just being put under the carpet (bugs that force me to save as a temporary project file each time I need to compile, for instance).
I don’t have the app nor the project on an external drive. But every time I run Xojo and compile, I have to add the license again and reactive it again and transfer it again. This is using Tahoe.
We ask anyone experiencing unexpected behavior with their license activation to share those in Issues so they can be looked into. As to the case Tim says he remembers but can’t find, I also cannot find anything like that, and @William_Yu can’t either. We’d love to fix any trouble users experience with licensing asap, but we need an Issue number with some details in order to reproduce it and begin an investigation. If you have filed or followed an Issue about this, please send it to me at hello@xojo.com.
General licensing troubleshooting in the Xojo Docs.
Edited to include docs link.