Learning Forum

[kelvin.k.kong]

Dear staff and fellow users, After successfully ran a simulation in Fluent Solutions, I clicked on File > Write > Case & Data to save my progress.
Is that the correct way of saving? Because when I tried to open it: File > Read > Case & Data:

 I was unable to open it, and this message popped up in the console: 

> Fast-loading "C:\PROGRA~1\ANSYSI~1\v251\fluent\fluent25.1.0\addons\afd\lib\hdfio.bin"

Done.

HDF5-DIAG: Error detected in HDF5 (1.12.2) MPI-process 0:

#000: C:\.conan\888d91\1\hdf5-1.12.2\src\H5F.c line 620 in H5Fopen(): unable to open file

major: File accessibility

minor: Unable to open file

#001: C:\.conan\888d91\1\hdf5-1.12.2\src\H5VLcallback.c line 3502 in H5VL_file_open(): failed to iterate over available VOL connector plugins

major: Virtual Object Layer

minor: Iteration failed

#002: C:\.conan\888d91\1\hdf5-1.12.2\src\H5PLpath.c line 579 in H5PL__path_table_iterate(): can't iterate over plugins in plugin path '(null)'

major: Plugin for dynamically loaded library

minor: Iteration failed

#003: C:\.conan\888d91\1\hdf5-1.12.2\src\H5PLpath.c line 713 in H5PL__path_table_iterate_process_path(): can't open directory

major: Plugin for dynamically loaded library

minor: Can't open directory or file

#004: C:\.conan\888d91\1\hdf5-1.12.2\src\H5VLcallback.c line 3351 in H5VL__file_open(): open failed

major: Virtual Object Layer

minor: Can't open object

#005: C:\.conan\888d91\1\hdf5-1.12.2\src\H5VLnative_file.c line 97 in H5VL__native_file_open(): unable to open file

major: File accessibility

minor: Unable to open file

#006: C:\.conan\888d91\1\hdf5-1.12.2\src\H5Fint.c line 1999 in H5F_open(): unable to read root group

major: File accessibility

minor: Unable to open file

#007: C:\.conan\888d91\1\hdf5-1.12.2\src\H5Groot.c line 228 in H5G_mkroot(): can't check if symbol table message exists

major: Symbol table

minor: Can't get value

#008: C:\.conan\888d91\1\hdf5-1.12.2\src\H5Omessage.c line 845 in H5O_msg_exists(): unable to protect object header

major: Object header

minor: Unable to protect metadata

#009: C:\.conan\888d91\1\hdf5-1.12.2\src\H5Oint.c line 1051 in H5O_protect(): unable to load object header

major: Object header

minor: Unable to protect metadata

#010: C:\.conan\888d91\1\hdf5-1.12.2\src\H5AC.c line 1426 in H5AC_protect(): H5C_protect() failed

major: Object cache

minor: Unable to protect metadata

#011: C:\.conan\888d91\1\hdf5-1.12.2\src\H5C.c line 2370 in H5C_protect(): can't load entry

major: Object cache

minor: Unable to load metadata into cache

#012: C:\.conan\888d91\1\hdf5-1.12.2\src\H5C.c line 7315 in H5C__load_entry(): incorrect metadata checksum after all read attempts

major: Object cache

minor: Read failed

#013: C:\.conan\888d91\1\hdf5-1.12.2\src\H5Ocache.c line 203 in H5O__cache_get_final_load_size(): can't deserialize object header prefix

major: Object header

minor: Unable to decode value

#014: C:\.conan\888d91\1\hdf5-1.12.2\src\H5Ocache.c line 1202 in H5O__prefix_deserialize(): bad object header version number

major: Object header

minor: Wrong version number

 

999999: mpt_accept: warning: connection timed out after 120 seconds

Error in the fluent (fl) process : ended abnormally

 

When I tried the second time:

Fast-loading "C:\PROGRA~1\ANSYSI~1\v251\fluent\fluent25.1.0\addons\afd\lib\hdfio.bin"

Done.

HDF5-DIAG: Error detected in HDF5 (1.12.2) MPI-process 0:

#000: C:\.conan\888d91\1\hdf5-1.12.2\src\H5F.c line 620 in H5Fopen(): unable to open file

major: File accessibility

minor: Unable to open file

#001: C:\.conan\888d91\1\hdf5-1.12.2\src\H5VLcallback.c line 3502 in H5VL_file_open(): failed to iterate over available VOL connector plugins

major: Virtual Object Layer

minor: Iteration failed

#002: C:\.conan\888d91\1\hdf5-1.12.2\src\H5PLpath.c line 579 in H5PL__path_table_iterate(): can't iterate over plugins in plugin path '(null)'

major: Plugin for dynamically loaded library

minor: Iteration failed

#003: C:\.conan\888d91\1\hdf5-1.12.2\src\H5PLpath.c line 713 in H5PL__path_table_iterate_process_path(): can't open directory

major: Plugin for dynamically loaded library

minor: Can't open directory or file

#004: C:\.conan\888d91\1\hdf5-1.12.2\src\H5VLcallback.c line 3351 in H5VL__file_open(): open failed

major: Virtual Object Layer

minor: Can't open object

#005: C:\.conan\888d91\1\hdf5-1.12.2\src\H5VLnative_file.c line 97 in H5VL__native_file_open(): unable to open file

major: File accessibility

minor: Unable to open file

#006: C:\.conan\888d91\1\hdf5-1.12.2\src\H5Fint.c line 1999 in H5F_open(): unable to read root group

major: File accessibility

minor: Unable to open file

#007: C:\.conan\888d91\1\hdf5-1.12.2\src\H5Groot.c line 228 in H5G_mkroot(): can't check if symbol table message exists

major: Symbol table

minor: Can't get value

#008: C:\.conan\888d91\1\hdf5-1.12.2\src\H5Omessage.c line 845 in H5O_msg_exists(): unable to protect object header

major: Object header

minor: Unable to protect metadata

#009: C:\.conan\888d91\1\hdf5-1.12.2\src\H5Oint.c line 1051 in H5O_protect(): unable to load object header

major: Object header

minor: Unable to protect metadata

#010: C:\.conan\888d91\1\hdf5-1.12.2\src\H5AC.c line 1426 in H5AC_protect(): H5C_protect() failed

major: Object cache

minor: Unable to protect metadata

#011: C:\.conan\888d91\1\hdf5-1.12.2\src\H5C.c line 2370 in H5C_protect(): can't load entry

major: Object cache

minor: Unable to load metadata into cache

#012: C:\.conan\888d91\1\hdf5-1.12.2\src\H5C.c line 7315 in H5C__load_entry(): incorrect metadata checksum after all read attempts

major: Object cache

minor: Read failed

#013: C:\.conan\888d91\1\hdf5-1.12.2\src\H5Ocache.c line 203 in H5O__cache_get_final_load_size(): can't deserialize object header prefix

major: Object header

minor: Unable to decode value

#014: C:\.conan\888d91\1\hdf5-1.12.2\src\H5Ocache.c line 1202 in H5O__prefix_deserialize(): bad object header version number

major: Object header

minor: Wrong version number

 

999999: mpt_accept: warning: connection timed out after 120 seconds

Error in the fluent (fl) process : ended abnormally

 

Note: Saved with 2025 R1. Trying to open in 2025 R1.

 Thanks!

[Rob]

That's correct. Are you running Fluent standalone? Can you save to a non OneDrive folder to check the folder set up. Finally, how are you for disc space and RAM; monitor the latter as you save the files?

[kelvin.k.kong]

 

Hi Rob,

Yes, I’m using Fluent standalone. Should I use Workbench to launch Fluent? 

I’m part of a university team, and our files are saved on Onedrive.
I saved the file with the laptop that I tried to open my saved file with, so file should be on my computer. (not waiting to be downloaded from the Onedrive Cloud)

My laptop that I run simulations, my 1TB hardrive is about half full, 128GB RAM. (Recent simulations used between 64 – 66GB ram, usually.)

Thanks.

 

[Rob]

OK, thanks. Use Fluent in standalone mode and save locally. If you can save to a non-Onedrive folder try that. RAM sounds good. Note, Onedrive is also a folder on the computer and I've seen problems with some versions of Win10 & 11 trying to upload/scan large files as they're written which can cause problems, hence if you can save in D:/ or C:/ away from it. How many cores are you running on? 

[kelvin.k.kong]

Hey Rob,

I'm on the full ANSYS Mechanical Enterprise and CFD Enterprise license. Using Double precison, and max cores I can use on my laptop is 8 cores. (8 Performance cores).

[Rob]

So Win10/11?  The licence type isn't an issue here, it's something OS related. Does saving to the root folder help? 128MB RAM on a laptop - I need to talk to Ansys IT before my next replacement check! 

[kelvin.k.kong]

 

I’m using Windows 11 Pro. 

Saving to C:/ results in this:

After that, Fluent won't let me perform tasks, all of the tasks either goes blank, or something weird happening to them:

Examples:

Values disappears.

Overlap in texts.

Same with after I try to import the initial simulation that I saved. I have to close Fluent and open it back up to be able to do tasks again.

 

[MangeshANSYS]

Hello I am jumping into this conversation with some suggestions Kevin and Rob.

1. When launching Fluent, please select mpi type as msmpi on the parallel tab of fluent launcher please 
2. just to double check, this is a "real" or "physical" Windows machine, right? this is not a VM or running MS Windows on a MacOS machine etc, right?
3. Please do not save directly to C:\ (root of C drive) instead always create a folder with no spaces such as C:\my_fluent_project\project_abcd\ etc and save there
4. please check drive properties for C: What is the file system type? hopefully it is NTFS. Is disk compression turned on ? it is off by default. 
   
5. Is the computer running any anti-virus which may interfere with writing files to disk or running the hdf5 compression that occurs during saving? by any chance can the system administrator temporarily disable the antivirus so you can test whether saving works when antivirus is turned off?
   
   hope one of these steps helps

[Rob]

That looks to be a cortex related failure - ie the head & display node has failed. Try without all of the spaces and double check write permissions. 

What happens if you switch to Legacy for file IO in the Preferences?

[kelvin.k.kong]

Try saving the name of simulation no spaces, with underscores?

I'll try saving without spaces first. 

Then if that doesn't work, I will try both without spaces and the legacy setting.

[kelvin.k.kong]

 

 

 

Attempt 1:

When I tried to save with underscores (no spaces), it didn’t successfully save:

I saved Case & Data after initialization, before running the simulation. This is the file which I have been using to run simulations.
Strange, because I am able to open this file which is also in my Onedrive, but not the post-simulation one?!

Q1) After my run simulation, do I just save data only, since I already have a case file from before, which I’m assuming won’t change, will it?

Attempt 2: Changing to Legacy setting before saving with underscores:

Tried to save in .cas .dat files…

But got this message:

Attempt 3 – Save by allowing myself to write:

Didn’t save successfully.

 

Attempt 4 – With CFF: I tried to save my pre-simulation case and data file that’s on my Onedrive to my C drive:
Strange.

Attempt 5 – With Legacy. I tried to save my pre-simulation case and data file that’s on my Onedrive to my C drive:

Could all this also be because I didn't save my mesh file with underscores? But Fluent Solutions still read it, and saved my pre-simulation case and data file.

 

[kelvin.k.kong]

 

Update:

Started Fluent as “ran as Admin”. Ran another test simulation to 500 iterations and completed (other sims I stopped the simulation myself. Not sure if it makes any difference to my issue, but I’ll just be detailed).

I was able to successfully save into my C drive and Onedrive:

C drive:

Then, I was able to open both Test files (Case&Data) from my C drive and Onedrive.

 

[Rob]

I'll get install to look. The save files should use/call all of the same solver routines so permissions shouldn't change, but something is blocking the drive from the Error: sopenoutput message. 

Whilst you don't need to save case file every time it's a good habit to do so. If you reorder the mesh the case and data won't match so I always save both. It's easy to delete files afterwards, but impossible to save after the fact!