What does “There are some data after the end of the payload data” mean

From what I can gather from your comments, it sounds like you are asking something else. It sounds like you are asking

1. What is the purpose of the Parameters field of the 7-zip dialog?
2. Why does it not work when you use the -o argument in that field?

If so, then the answers are simple (and related):

1. The Parameters field is for specifying any options you need that are not available via dedicated dialog controls.

2. The -o argument is ignored in the Parameters field because there is already a dedicated dialog control for the destination. The controls override corresponding options in the Parameters field.

Think about it this way, if you want to specify arguments in the Parameters field that already have dialog controls, then why use the GUI at all, why not just use the command-line in the first place? The dialog controls provide most options that are used and also reduce the possibility of error by specifying valid options. For example, the word-size options are already listed in the drop-down, so you cannot choose an invalid size like you can when specifying it in the Parameters field or command-line.

Some examples of usage of the Parameters field include:

• One such argument is exclusion (-x switch). If you want to specify filenames to be excluded, there is no option to do so in the dialog, and so you would have to enter them in the Parameters field.

• You would also use it to specify the -y switch to automatically say yes to everything instead of prompting you.

• You can even use it to override some of the options that the dialog automatically sets such as subdirectory recursion. When you use the dialog, it automatically sets recursion. If you don’t want that, you would need to specify -r- in the Parameters field.

For a full list, you can look at the list of command-line arguments (7z /?) and compare it to the controls in the dialog.

I suggest you use the 7-Zip Command Line Version (7za.exe).

A command like the following will redirect all output (including from stderr) to Log.txt:

7za a Test.7z *.* >Log.txt 2>&1

Additionally, 7-Zip returns the following exit codes which you can use in your batch file with %ERRORLEVEL%:

0 = No error.

1 = Warning (Non fatal error(s)). For example, one or more files were locked by some other application, so they were not compressed.

2 = Fatal error.

7 = Command line error.

8 = Not enough memory for operation.

255 = User stopped the process.

Edit: If you don't want such a verbose log containing all those Compressing <filename> lines, use this command instead:

7za a Test.7z *.* | findstr /i /v "pavlov scanning compressing" >Log.txt 2>&1

(The findstr command with switches above excludes all lines containing the words within quotes.)