Generally Excel have a lot of restrictions when opening files (can’t open the same file twice, can’t open 2 different files with the same name ..etc).
I don’t have excel on machine to test, but checking the docs for read_excel I’ve noticed that it allows you to set the engine.
from the stack trace you posted it seems like the error is thrown by xlrd which is the default engine used by pandas.
try using any of the other ones
Supported engines: “xlrd”, “openpyxl”, “odf”, “pyxlsb”, default “xlrd”.
so try with the rest, like
df = pd.read_excel(fPath, sheetname="linear strategy", index_col="date", parse_dates=True, engine="openpyxl")
I know this is not a real answer, but you might want to submit a bug report to pandas or xlrd teams.