[FIXED] Unusually large aup3 (bug with single-quote in directory)

I have removed that post.

Is it OK to refer to it as your “A” drive?
This may be very relevant to the problem.


Later today I’ll be pursuing the same workflow that produced that file; let’s see if I can reproduce this.

If the original project was on your A drive, then another thing that you could try:

Move or copy the project to your C:\ drive, then open the project (on the C:\ drive) and:

  • Reverse the first track
  • Undo
  • Save
  • Exit

Due to security constraints, it cannot be placed raw under C:\ but must be in a subdirectory.

With this advice, I explored different .aup3 file locations and learned to reproduce the problem.

Under some circumstances the file size will not change, and in others it will change to a reasonable:

186 MB (195,297,280 bytes)

Directory structures which produce 1.35 GB (i.e. no change) contain a single quote mark ( ’ ):

1.35 GB (1,453,326,336 bytes)


This is an NTFS filesystem on Windows 10.

In case it matters, I learned the block size is 4096 using PowerShell and this command:

Get-CimInstance -ClassName Win32_Volume | Select-Object Label, BlockSize | Format-Table -AutoSize

Other directory structures will produce 186 MB:



I only eyeballed the file size for most tests; I did not confirm exactly.

Yes, that’s normal for Win 10.
I meant putting the project in a normal directory on the C: drive. The default directory for Audacity is C:\Users<user name>\Documents

Do you mean that any directory that contains an apostrophe (single quote) in the file path causes the problem?
I found this: How Can I Connect to a Folder When There’s an Apostrophe in the Folder Name? - Scripting Blog [archived]

Hey, JO. Ah, the apostrophe (also known as the single quote mark). It seems like such a simple little character, and yet it has probably caused script writers more grief than any other character on the keyboard. (Yes, even more than ~.)

The problem is that the apostrophe is a “reserved” character in both VBScript and WMI; that means these scripting technologies want to reserve the use of the apostrophe for themselves. That’s fine, except when dealing with folder names like Ken Myer’s folder or people names like O’Donnell or O’Hara. You want to use the apostrophe, because how else can you write the name Ken Myer’s Folder? Meanwhile, VBScript and WMI want exclusive use of the apostrophe for other reasons. As you might expect, that leads to problems.

Does that sound like the problem?
If that’s it, I think we should be able to fix the next Audacity version.

Yes, that appears to be it. I can reproduce the problem here (on Linux).
Good work syeedali :mrgreen:

Thanks to your observation about single quotes, one of the developers has come up with a fix for the next Audacity release.
For now, the work around is to avoid using file paths that contain a single-quote character (').

Thanks for sticking with us on this syeedali and for all of your testing.

Thanks also to you. :slight_smile:

As for reproducing the problem, presumably it was caused by writing into a folder with an apostrophe, but I’ll keep an eye on it.

Yes, that’s correct.
Audacity “should” have been escaping the single-quote character, but it wasn’t doing that, and that caused “compaction” to fail.

Normally Audacity should remove unused data from the project and “compact” the project file to fit the data. That wasn’t happening if the file path contained a single-quote character. James fixed it here: Bug 2793 - AUP3 projects fail to compact if project's path contains a… · audacity/audacity@df91d14 · GitHub

The developers will also be making some small changes to error reporting, so that if anything like this happens again, there will be some sort of error message rather than just failing silently.