I did a test, and my input file is attached:  benzene_S1.wfn. I didn't find the same issue on both Windows and Linux versions. Perhaps "ulimit -s unlimited" didn't take effect, please check.

Best,

Tian

#p B3LYP/6-31+G(d) TD(Singlets, NStates=3, Root=1) Density=Current Output=WFN

Using wfn file, I tried to calculate FLU index but the error message occurred like below.

                 ======== Fuzzy atomic space analysis ========
-10 Set X,Y,Z of reference point, current:    0.00000   0.00000   0.00000 Bohr
-6 Choose type of integration grid for AOM, current: Atomic grid
-5 Define the atoms to be considered in options 1, 2, 13, current: all atoms
-4 Adjust reference parameter for FLU
-3 Set the number of iterations for Becke partition, current:  3
-2 Select radius definition for Becke partition, current: Modified CSD
-1 Select method for partitioning atomic spaces, current: Becke
0 Return
1 Perform integration in fuzzy atomic spaces for a real space function
2 Calculate atomic and molecular multipole moments and <r^2>
3 Calculate and output atomic overlap matrix (AOM) in current folder
33 Calculate and output fragment overlap matrix (FOM) in current folder
4 Calculate localization (LI) and delocalization index (DI)
44 Calculate fragment LI (FLI) and interfragment DI (IFDI)
5 Calculate PDI (Para-delocalization index)
6 Calculate FLU (Aromatic fluctuation index)
7 Calculate FLU-pi
8 Perform integration in fuzzy overlap region for a real space functions
11 Calculate multi-center delocalization index
12 Calculate information-theoretic aromaticity index (ACS Omega, 3, 18370)
13 Calculate atomic effective volume, free volume, polarizability and C6 coefficient
Note: All orbitals are taken into account in AOM calculation
Allocating memory...
Radial points:   45    Angular points:  170   Total:      7650 per center
Please wait...

Progress: [--------------------------------------------------]     0.0 %     -^Mforrtl: severe (174): SIGSEGV, segmentation fault occurred

I saw that the command 'ulimit -s unlimited' can resolve this issue, so I tried it but it didn't work well.
I installed Multiwfn in linux server, and due to a minor problem during installation, Multiwfn_noGUI is utilized to run Multiwfn.
Any comments would be surely helpful for treating this problem.

Sincerely,
Jonghwan Lee