[dune-pdelab] Unknown exception

[conf86 at web.de]

I don't know if this DUNE related enough to be asked here, but I got the "unknown exception" error during calculation.

I executed the program and it calculated 263 time steps, then I got the error:

TIME STEP [Alexander (order 2)]    263 time (from):   2.6200e+1 dt:  
1.0000e-1 time (to):   2.6300e+1
STAGE 1 time (to):   2.6229e+1.
=== matrix setup skipped (matrix already allocated)
=== matrix assembly (max) 0.07737 s
=== residual assembly (max) 0.009837 s
=== solving (reduction: 1e-10) 0.003325 s
STAGE 2 time (to):   2.6300e+1.
=== matrix setup skipped (matrix already allocated)
=== matrix assembly (max) 0.05561 s
=== residual assembly (max) 0.008909 s
=== solving (reduction: 1e-10) 0.003059 s
::: timesteps         263 (263)
::: nl iterations    1575 (1575)
::: lin iterations   1575 (1575)
::: assemble time    4.0507e+01 (4.0507e+01)
::: lin solve time   1.6890e+00 (1.6890e+00)
Unknown exception thrown!
terminate called after throwing an instance of 'std::ios_base::failure'
  what():  basic_ios::clear
Aborted (core dumped)

The calculated data also look normal until the 263th step.
The calculations were fine previously, the only thing I did was changing some parameters/terms in the code and the mesh (unfortunately I didn't make any backup). I tried to change it back, but the error remained. 

Do you have any idea where this might come from? 


Best regards