File error (Incorrect CRC) with drag and drop operation from UltraIso

Help & Support
1

Hello,

I have a trouble when I drag and drop a file from UltraIso (9.7.0.3476) to Directory Opus (12.7).
The CRC of the file is incorrect.
If I do the same operation from UltraIso to the Windows Explorer (of Windows 10), the CRC is correct.

Do you have a idea ?
In the mean time, I have open a ticket to the support of UltraIso Team :wink:

Thanks for your support
Laurent

2

One thing to try is setting Preferences / Miscellaneous / Advanced: dragdrop_async = False.

Is the file size correct, or also different? (zero?)

What's being used to check the CRC? Is the CRC about the source data inside the iso or the destination data after it's extracted?

Does an error message appear, or are you comparing the CRC yourself as a separate step? If there is an error message, could you post a screenshot of it so we can see which software it's coming from?

3

Hello Leo,

Same result with the parameter set to false.
The file size is correct and exactly the same.
To calculate the hash, I'm using HashTab. The value is also the same calculate by UltraIso.
I think you can try from your side with the demo version (http://www.ezbsystems.com/ultraiso/download.htm).
No error appears during the drag and drop operation.

For info, if I do the same from winrar or Daemon tools to Director Opus the file is correct.

Regards
Laurent

4

Which type(s) of files is it happening with? Have you looked at the differences to see what has changed inside them? e.g. It could be metadata that is changing, which might indicate why or what is changing. Or it might be that some of the file is all zeros which could indicate something else.

If you want, zip up a before & after version of a small file and I can compare the two to see if it suggests what might be happening.

5

Hello Leo
The problem is only with all files extracted from iso files produced by Passcape.
If I extract a file from a Iso with drag and drop from other Iso, like Paragon or other Iso it's ok.

Inside the file extracted, they are some gaps filled by zeros instead of normal data (eg. between the hex offset 7E0 until 7FFF0).

The link of the original ISO from Passcape:
https://www.passcape.com/index.php?section=downloads&download=4

Please find a zip file with 3 sorts of files, in binary you will see the problem.
rwpd.zip (2.3 MB)

Regards

6

Thanks for reporting this and the extra information.

This seems to be a bug in UltraISO. When you do a drag and drop to Opus from UltraISO, it provides a "stream" that we read data from. By trial and error I've confirmed that it works fine if we try to read no more than 522239 bytes at once.

The default copy buffer size in Opus is 512KB (524288 bytes) so this is what's triggering the problem. Presumably Explorer uses a smaller copy buffer size and so they've never noticed this problem (as they've probably only ever tested it against Explorer).

We'll add a workaround for this in the next version but in the meantime you should be able to fix it by setting the copy buffer size (Preferences / Miscellaneous / Advanced: copy_buffer_size) to something less than 522239 bytes (e.g. change it to 256KB).

(My theory is UltraISO uses a fixed-size internal buffer when it implements its drag&drop data source, and they aren't properly checking the requested data size against that limit. 522239 seems like a strange number to pick in decimal, but in hex it's 0x7f7ff which looks more like a "round number" and it's also a prime number, which may have appealed to someone's nerdy sense of humour :slight_smile: )

7

Hello,

Thanks for your support.
You explaination is clear. I have transmitted your answer to the support of UltraIso, may be this bug can be corrected in UltraIso.
I have tested your solution successfully.

I very happy to bought Directory Opus. It's a powerfull software with a lot integrated great ideas.
And a big bonus a very good support and also fast to help us when we found some problems :sunglasses:

Regards
Laurent

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