Why saving of MSWord document can silently fail?

Question

I need to change some custom properties values in many files. Here is an example of code - how I do it for a single file:

import win32com.client

MSWord = win32com.client.Dispatch("Word.Application")
MSWord.Visible = False

doc = MSWord.Documents.Open(file)
doc.CustomDocumentProperties('Some Property').Value = 'Some New Value'
doc.Save()
doc.Close()

MSWord.Quit()

Running the same code for "Excel.Application" (with minor changes - just to make it work) gives me excellent result. However when I'm using doc.Save() or doc.SaveAs(same_file) for MSWord it silently fails. I don't know why, but changes are not saved.

Now my workaround is to use SaveAs to a different file, it also works good. But I want to understand why I have such strange behaviour for MSWord files and how it can be fixed?

Edit: I changed my code, not to misdirect people with silent fail cause of try/except. However, thanks to all of them for finding that defect in my code :)

Answer 1

(a) Check to see if you have file write access

(b) Make sure you code catches using the COMException

(C) are you gracefully terminating excel/words when creating multiple documents

Darknight

Answer 2

It fails silently since you ignore errors (except: pass).

The most common reason why saving a Word file usually fails is that it's open in Word.

Answer 3

you're saving file only if Value was successfully changed. May be you could try to remove try-except clause and see what is actually happening when you're file is not saved. And, btw, using bare except is not a good practice.

Answer 4

You were using the CustomDocumentProperties in the wrong way, and as other people pointed out, you could not see it, because you were swallowing the exception.

Moreover - and here I could not find anything in the documentation - the Saved property was not reset while changing properties, and for this reason the file was not changed.

This is the correct code:

msoPropertyTypeBoolean = 0
msoPropertyTypeDate = 1
msoPropertyTypeFloat = 2
msoPropertyTypeNumber = 3
msoPropertyTypeString = 4

import win32com.client

MSWord = win32com.client.Dispatch("Word.Application")
MSWord.Visible = False

doc = MSWord.Documents.Open(file)
csp = doc.CustomDocumentProperties
csp.Add('Some Property', False, msoPropertyTypeString, 'Some New Value')
doc.Saved = False
doc.Save()
doc.Close()

MSWord.Quit()

Note: there is no error handling, and it is definitely not of production quality, but it should be enough for you to implement your functionality.
Finally, I am guessing the values of the property types (and for the string type the guess is correct) but for the others there could be some issue.