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Over the last few days, I have been working on automating the generation of some pivot tables for a number of reports.

Boiled down to the minimum, the following code was working without issue:

import win32com.client objExcelApp = win32com.client.gencache.EnsureDispatch('Excel.Application') objExcelApp.Visible = 1

Explain

This would pop-up an instance of excel and I could continue working in Python. But suddenly, today my scripts are failing with the following:

module 'win32com.gen_py.00020813-0000-0000-C000-000000000046x0x1x9' has no attribute 'CLSIDToClassMap'

I had the same issue and I resolved it by following the instructions here: https://mail.python.org/pipermail/python-win32/2007-August/006147.html

Deleting the gen_py output directory and re-running makepy SUCCEEDS and subsequently the test application runs OK again.

So the symptom is resolved, but any clues as to how this could have happened. This is a VERY long running application (think 24x7 for years) and I'm concerned that whatever caused this might occur again.

To find the output directory, run this in your python console / python session:

import win32com print(win32com.__gen_path__)

Explain

or, even better, a one-liner in the command line:

python -c "import win32com; print(win32com.__gen_path__)"

Explain

Based on the exception message in your post, the directory you need to remove will be titled '00020813-0000-0000-C000-000000000046x0x1x9'. So delete this directory and re-run the code. And if you're nervous about deleting it (like I was) just cut the directory and paste it somewhere else.

💡Note that this directory is usually in your "TEMP" directory (copy-paste %TEMP%/gen_py in Windows File Explorer and you will arrive there directly).

I have no idea why this happens nor do I know how to prevent it from happening again, but the directions in the link I provided seemed to work for me.

https://stackoverflow.com/a/54422675