# Known bugs¶

This page lists a number of known bugs or issues in released versions of MESA. Where possible we will also list work arounds, but for some bugs the only option will be to update to a newer version of MESA. Note this list is NOT comprenhisive, users should check this first if they have an issue but it may not be complete.

## r21.12.1¶

### Al26 isomers¶

After running a model with the al26 isomers in your net, when you run the model again, it immediatly crashes and prints a backtrace containing:

create initial model
create rate data for r_al26-1_to_al26-2
create rate data for r_al26-2_to_al26-1

Program received signal SIGSEGV: Segmentation fault - invalid memory reference.

Backtrace for this error:
#0  0x7fd69c02931f in ???
at /usr/src/debug/glibc-2.33-20.fc34.x86_64/signal/../sysdeps/unix/sysv/linux/x86_64/sigaction.c:670
#1  0x99a523 in __interp_1d_misc_MOD_do_interp_values


The solution for now is to remove all files in \$MESA_DIR/data/rates_data/cache/ before each MESA run.

See gh-360

### Atmosphere in pulse data¶

The control add_atmosphere_to_pulse_data does not work properly with an Eddington atmosphere (the default), and also crashes if atm_T_tau_opacity = 'varying' is set.

See gh-375

If you get an error:

bad filter name:


First check that the name matches in your history_coloumns.list file and your color file. Next check for non-printing characters history_coloumns.list in the filter name. This can bee checked with:

cat -A history_columns.list | grep "abs_mag"


Finally, there is a bug if you name the any coloumn with either [] characters in there (for instance [Fe/H]). The solution is to rename the column to remove the square brackets.

See gh-379