Unpacked Backup is Empty

[zedseven]

Extracting an encrypted backup yields a *.tar file that is exactly 1024 bytes long, all of which are 00. I have tried backing up a few apps, all of which to the same result.

These are the exact commands I have run:

./adb.exe backup -f ./com.fedex.ida.android.ab -noapk com.fedex.ida.android

java -jar ./abe-all.jar unpack "com.fedex.ida.android.ab" "com.fedex.ida.android.tar" 1111

And running java -version yields:

java version "1.8.0_221"
Java(TM) SE Runtime Environment (build 1.8.0_221-b11)
Java HotSpot(TM) Client VM (build 25.221-b11, mixed mode)

I have attached a sample app backed up from my old phone (LG G6) encrypted with the password '1111'

The contents of the extracted *.tar archive:

[n-eq]

Hi,
I just ran into the same issue.

However, I have a slightly different configuration :

[23:28] $ java -version
openjdk version "11.0.5" 2019-10-15
OpenJDK Runtime Environment (build 11.0.5+10-post-Ubuntu-2ubuntu116.04)
OpenJDK 64-Bit Server VM (build 11.0.5+10-post-Ubuntu-2ubuntu116.04, mixed mode, sharing)

The commands I performed :

[23:23] ~/tmp$ java -jar ~/Downloads/abe.jar unpack packpack.ab packpack.tar 1234
Calculated MK checksum (use UTF-8: true): <hash>
3% 
1024 bytes written to packpack.tar.
[23:32] ~/tmp$ java -jar ~/Downloads/abe.jar unpack packpack.ab packpack.tar
[23:32] ~/tmp$ ls -lh packpack.tar 
-rw-rw-r-- 1 marrakchino marrakchino 1.0K Mar 15 23:28 packpack.tar

The same commands yields a 1.0K tar empty archive (nothing extractable).
I used a Samsung Galaxy S8 (Android 9, API 28) phone in the process.

Any updates ?
Best

[stachenov]

Same here. I was hoping to export MS Outlook configuration this way, so I could then import it on a PC. Not sure if that is possible at all, but couldn't even get past the export step: got tar of 1024 zero bytes.

[stachenov]

Looking at the source file, it's hard to believe it contains any useful data. It's just too small for that (549 bytes). So I wouldn't blame the extractor for it. It's that adb just can't make backups of certain apps on certain phones. Why, I have no idea.

[nelenkov]

Apps can disable backup of their data. Different Android versions handle this differently, some produce empty backups (0 bytes), some output header with no data. ADB backup is being deprecated, so no guarantees.
You could try enabling developer options and setting a backup password there, but very much depends on device, Android version, and app settings combintation.

[stachenov]

Right, that's exactly what I'm thinking. I tried to make a full backup of all apps and found that data for some apps is present, while for others it's not.

And it is certainly not Extractor's fault because it is obvious from 549-byte size of the original *.ab file that it was empty to begin with. No way Extractor can extract some useful data from an empty file. Same with the file attached by the OP (it's also 549 bytes).

[gsgrippal]

com.fedex.ida.android does not allow backup, you have to modify apk to work

[superbonaci]

@zedseven close this issue it's the app's fault.