I had the same problem; it appeared after I have renamed a monitor I created earlier; after deleting the monitors this error disappeared.

OMG, it works when I restart! lol
thanks, Learner.

I solved this problem the same way. However, I found that it was only two of my monitors which were causing the issue (I applied the process of elimination). I deleted and then redefined those monitors, after which the problem disappeared.

Thanks caitoc
I had the same problem and it works by resetting the solution setup

cdr: invalid argument [1]: wrong type [not a pair] Error object: #f
 

I recently encountered this problem while running fluent 15.0 and determined it was caused by my convergence monitors.

More specifically, the iterations to ignore appear to be have been the root cause; when set to ignore the first 500 iterations the solution always threw this error once the solution reached and attempted to exceed 500 iterations. Once the convergence monitors were removed, problem no longer persisted.

SOLUTION:

Remove/Replace convergence monitors (see iterations to ignore).

Thanks Tank!
I just solved my problem as you said, deleting all monitors. A detail is that you can't delete residual monitors, but it is fine anyway.

i found the problem on my side. If you have zero for inlet BC, then you will get this error. I am using a journal file and set the velocities there, but thought i could leave the inlet BCs as zero. Nope.

i face to this error when i decided to active nist real gas.
any idea how to fix it ?

Just giving it a break seems to help. Try stopping the simulation, then restarting it after a while

it is old but the solution is that some file isn't correctly loaded. Try refresh upstream components , or if you are trying to open the solution open and close first the setup before to fix the problem.

Hey everybody,

just want to confirm what Tank said. Removing my monitors and reports solved the problem. Interesting. However, I needed to load the data create from 20 R2 into 20 R1 as I need to export the data for ParaView and for some reasons the 20 R2 version does not work.

Probably there is a change in the file which needs to be incorporated into the ParaView reader first.

I also have not found a better way than to delete and create the reports again.

Fortunately I am going back to OpenFOAM. Fluent has some very interesting features I miss in FOAM but the GUI is so buggy in my personal opinion. It crashes several times each day.

I solved the problem based on the following situation: I opened the 2021 version of the fluent case with the 2020 version of fluent, and the error occurred, and the problem can be solved by recreating the case.

Removing monitors works!
 

Thanks @Tank. Same issue in my case is solved after removing all the monitors.

For me it is the number of inconsistent inputs
 

I am using scheme to write a journal file in fluent

(Do (( x 1 (+ x 1)))((> x 13))
(begin
(Ti-menu-load-string (format #f "file/transient-export/ascii plane~a pplane~a () x-velocity () yes no export-~a 1 time-step" x x x))
))

My command here tries to export 13 files "plane~a", on 13 different planes "pplane-~a", and name each of them "export-~a"...

I have got the same error
Error: CAR: invalid argument [1]: wrong type [not a pair]
Error Object: ()

I realized it when I was editing my Matlab file
e.g.
for i=1:100
name = sprintf('name-%d%d%d',i,i,i);
end


For the number of references in the command ~a of scheme, we have to input the same number of variables.
In my command I had 3 ~a
then I have to input three "x" for it to work.

Hi,I want to offer another solution method that might help.
Pls restart Fluent using DOUBLE precision option.