python - pd.read_excel throws PermissionError if file is open in Excel

Question

Whenever I have the file open in Excel and run the code, I get the following error which is surprising because I thought read_excel should be a read only operation and would not require the file to be unlocked?

    Traceback (most recent call last):
  File "C:UsersPublica.py", line 53, in <module>
    main()
  File "C:UsersPublicworkspacea.py", line 47, in main
    blend = plStream(rootDir);
  File "C:UsersPublicworkspacea.py", line 20, in plStream
    df = pd.read_excel(fPath, sheetname="linear strategy", index_col="date", parse_dates=True)
  File "C:UsersPublicContinuumAnaconda35libsite-packagespandasioexcel.py", line 163, in read_excel
    io = ExcelFile(io, engine=engine)
  File "C:UsersPublicContinuumAnaconda35libsite-packagespandasioexcel.py", line 206, in __init__
    self.book = xlrd.open_workbook(io)
  File "C:UsersPublicContinuumAnaconda35libsite-packagesxlrd\__init__.py", line 394, in open_workbook
    f = open(filename, "rb")
PermissionError: [Errno 13] Permission denied: '<Path to File>'

Answer 1

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.