Error messagge when creating a process : Failed to create save RootEntity

Question

Good morning,

I downloaded openLCA few days ago (version 1.7) and used the PET bottle case study (even if for 1.5 version) to understand how to create my own case of study (quite similar to the case study of PET bottle). Till yesterday everything was ok. Since yesterday evening I got this error message: 
 

Failed to create save RootEntity

I follow the same instructions of the PET case study (that till yesterday were working and giving same results of the online example):
1) I create a child category in the flows folder
2) I create flows giving them reference quantities and specifying that are products
3) I create a child category in the process folder (with the same name of the one in the flows folder)
4) I try to create the new process in this folder selecting the reference quantity from the flow and I do not succeed since I got the above mentioned error message.

What could it be?

Comments

Have you simply tried to create a new instance of the database and to retry it in the new database

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Yes, I have tried to re-import the same database and create my process in it.... got the same error message

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Many thanks for posting the error. With a search on the code I can locate where this occurs: https://github.com/GreenDelta/olca-app/search?q=%22Failed+to+create+save%22&unscoped_q=%22Failed+to+create+save%22
However, if you could post the text of the complete error from the log file that would be helpful to reproduce it.