Excel file corrupted if running dash app simultaneously in two browser tabs

[jlfsjunior]

That was my expectation, that you would have the same file opened multiple times.

I think your fix is good, but if you don’t want to create the files in the backend, you could try an approach like this:

Generate multiple tabs in Excel file with dcc.send_data_frame()

I hope my answer will help someone else. I found the solution with dcc.send_file() is not as convinient as dcc.send_data_frame(). You have to store a lot of files inside your project folder. Solution that worked for me is dcc.send_bytes() import io output = io.BytesIO() writer = pd.ExcelWriter(output, engine='xlsxwriter') df_1.to_excel(writer, sheet_name='sheet_1', index=False) # writes to BytesIO buffer df_2.to_excel(writer, sheet_name='sheet_2', index=False) df_3.to_excel(writer, sheet_name=…