The best way to start solving an issue in ReproZip is probably to look at the log messages. Some messages are not displayed by default when running ReproZip, but you can use the --verbose (or -v) flag to display them. In addition, all the log messages are stored under $HOME/.reprozip/log.

Please feel free to contact us at if you encounter issues while using ReproZip.

Issue: reprozip does not identify my input/output file.”
Diagnosis:ReproZip uses some heuristics to identify an input or output file. However, this is only intended to be a starting point, since these heuristics may fail.
Solution:You should check the configuration file and edit the inputs_outputs section if necessary; giving readable names to input/output files also helps during reproduction. Please refer to Editing the Configuration File for more information.


“None of my files are packed when tracing a daemon.”


If you are starting the daemon via the service tool, it might be calling init over a client/server connection. In this situation, ReproZip will successfully pack the client, but anything the server (init) does will not be captured.


You can still trace the binary or a non-systemd init script directly. For example, instead of:

$ reprozip trace service mysql start

you can trace either the init script:

$ reprozip trace /etc/init.d/mysql start

or the binary:

$ reprozip trace /usr/bin/mysqld

Note that, if you choose to trace the binary, you need to figure out the right command line options to use. Also, make sure that systemd is not called, since ReproZip and systemd currently do not get along well.


reprozip fails with couldn't use ptrace


ptrace is the mechanism that ReproZip uses to attach to another process and follow its system calls. Because it is so powerful, some security policies, environments or isolation mechanism may disable it.


Issue: reprounzip cannot get an output file using download after reproducing the experiment.”
Diagnosis:This is probably the case where this output file does not have a fixed path name. It is common for experiments to dynamically choose where the outputs should be written, e.g.: by putting the date and time in the filename. However, ReproZip uses filenames in the inputs_outputs section of the configuration file to detect those when reproducing the experiment: if the name of the output file when reproducing is different from when it was originally packed, ReproZip cannot detect these as output files, and therefore, cannot get them through the download command.
Solution:The easiest way to solve this issue is to re-pack the experiment: write a simple bash script that runs the experiment and either renames outputs or creates symbolic links to them with known filenames; then, trace this script (instead of the actual entry-point of your experiment) and specify these fixed path names in the inputs_outputs section of the configuration file.

Issue: reprounzip-vagrant installation fails with error Unable to find vcvarsall.bat on Windows.”
Diagnosis:Python is trying to build PyCrypto, one of the dependencies of reprounzip-vagrant, but there is no C compiler available.
Solution:You can either build PyCrypto from source, or follow the instructions on this website to get the non-official binaries.


reprounzip-vagrant installation fails with error unknown argument: '-mno-fused-madd' on Mac OS X.”


This is an issue with the Apple LLVM compiler, which treats unrecognized command-line options as errors.


As a workaround, before installing reprounzip-vagrant, run the following:

$ export CFLAGS="-Wno-error=unused-command-line-argument-hard-error-in-future"

Then, re-install reprounzip-vagrant:

$ pip install -I reprounzip-vagrant

Or use the following command in case you want all the available plugins:

$ pip install -I reprounzip[all]

Issue:“The experiment fails with Error: Can't open display: :0 when trying to reproduce it.”
Diagnosis:The experiment probably involves running a GUI tool.
Solution:The reprounzip component supports GUI tools, but it is not enabled by default; add the flag --enable-x11 to the run command to enable it. See Can ReproZip pack graphical tools? for more information.

Issue:“The experiment run with reprounzip directory fails to find a file that has been packed.”
Diagnosis:The directory unpacker does not provide any isolation from the filesystem: if the experiment being reproduced use absolute paths, these will point outside the experiment directory, and files may not be found.
Solution:Make sure that the experiment does not use any absolute paths: if only relative paths are used internally and in the command line, reprounzip directory should work. As an alternative, you can use other unpackers (e.g.: reprounzip chroot and reprounzip vagrant) that work in the presence of hardcoded absolute paths.


reprounzip fails with DistributionNotFound errors.”


You probably have some plugins left over from a previous installation.


Be sure to upgrade or remove outdated plugins when you upgrade reprounzip. The following command may help:

$ pip install -U reprounzip[all]

Issue: reprounzip shows running in chroot, ignoring request .”
Diagnosis:This message comes from the systemd client, which will probably not work with ReproZip.
Solution:In this case, the experiment should be re-packed without using systemd (see this issue for more information).


reprounzip vagrant setup fails to resolve a host address.”


When running reprounzip vagrant setup, if you get an error similar to this:

==> default: failed: Temporary failure in name resolution.
==> default: wget: unable to resolve host address ...

there is probably a firewall blocking the Vagrant VM to have Internet connection; the VM needs Internet connection to download required software for setting up the experiment for you.


Make sure that your anti-virus/firewall is not causing this issue.


“The experiment fails because of insufficient memory in Vagrant.”


It is possible that the default amount of memory allocated to the VM is insufficient for the experiment. You can see a lot of different messages there, including:

  • Out of memory
  • Could not allocate memory
  • Killed

From VirtualBox, stop the machine and allocate more memory under Settings > System > Motherboard > Memory.

You can also use the --memory option when you run reprounzip vagrant setup to specify the amount of memory (in megabytes) at that time.


reprounzip run fails with no such file or directory or similar.”


This error message may have different reasons, but it often means that a specific version of a library or a dynamic linker is missing:

  1. If you are requesting reprounzip to install software using the package manager (by running reprounzip installpkgs), it is possible that the software packages from the package manager are not compatible with the ones required by the experiment.
  2. If, while packing, the user chose not to include some packages, reprounzip will try to install the ones from the package manager, which may not be compatible.
  3. If you are using reprounzip vagrant or reprounzip docker, ReproZip may be failing to detect the closest base system for unpacking the experiment.
  1. Use the files inside the experiment package to ensure compatibility.
  2. Contact the author of the ReproZip package to ask for a new package with all software packages included.
  3. Try a different base system that you think it is closer to the original one by using the option --base-image when running these unpackers.


“There are warnings from requests/urllib3 when running ReproZip.”

InsecurePlatformWarning: A true SSLContext object is not available. This
prevents urllib3 from configuring SSL appropriately and may cause certain SSL
connections to fail. For more information, see

Most Python versions are insecure, because they do not validate SSL certificates, thus generating these warnings.


If you are using Python 2.7.9 and later, you shouldn’t be affected, but if you see InsecurePlatformWarning, you can run pip install requests[security], which should bring in the missing components.