I'm trying to convert a folder of xml that was created by unzipping an excel file back into an excel .xlsx. But I get the error

>The workbook cannot be opened or repaired by Microsoft Excel because it is corrupt

The actual file I want to recreate is a fairly large macro-enbled .xlsm spreadsheet created with Excel 2016. I am using the xml format to archive in a git repository in order to provide version control. However, restoring a version from the archive requires that I can reverse the process.

However, a minimal example with a simple spreadsheet also reproduces this issue.

**A minimal reproducible example to generate this error:**

1. Create a new blank spreadsheet in Excel
2. Enter "test" in cell A1
3. Save as `test.xlsx`
4. Rename file to `test.zip`
5. Unzip `test.zip` as a folder named `test`
6. Compress `test` into `test_new.zip`
7. Rename `test_new.zip` as `test_new.xlsx`
8. Open `test_new.xlsx` with Excel



I am using Excel 2016. For zipping/unzipping I've tried 7zip, WinZip and Peazip, all with the same result.

What am I doing wrong, and how can I turn unzipped excel workbooks back into their original form?

The process you described works fine for me using WinZip with its default settings. I have no experience with 7-zip.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]

Updated question to note that I've tried with a few different zip tools -all with the same result

@Macropod Thanks for trying - I've attempted this now with WinZip, 7zip and PeaZip - all with the same result. What version of Excel are you using? Could it be related to the excel version perhaps?

As my profile indicates, I'm using Office 2010. That isn't the issue, however, as both is and Office 2016 use the same file format. Apparently, you're not recreating a zip file with exactly the same contents and structure as the original.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]

Ok I finally managed to solve this myself. The key is that when recreating the zip file, you must zip the contents of the unzipped folder. Not the folder itself!