# NLME error population PK model **URL:** \ **Category:** General\ **Created:** [April 24, 2026, 2:11am UTC](https://forum.certara.com/t/nlme-error-population-pk-model/4383 "2026-04-24T02:11:21Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![Harikrishna\_Devalapa](https://avatars.discourse-cdn.com/v4/letter/h/ecc23a/32.png) [@Harikrishna\_Devalapa](https://forum.certara.com/u/Harikrishna_Devalapa)\ **Post date:** [April 24, 2026, 2:11am UTC](https://forum.certara.com/t/nlme-error-population-pk-model/4383/1 "2026-04-24T02:11:21Z")
Hi All, I just recently run NLME in Phoenix and got below error. Error in Population: Error reading file C:\Users\HARIKR~1.DEV\AppData\Local\Temp\1\Phoenix\DME\_SI~1.605\out000001.txt: File does not exist There are errors during model execution. is this file created by model and not saved and accessible to execute the model? How to fix it. Thank you so much in advance. ---
**Author:** ![SimonDavis](https://avatars.discourse-cdn.com/v4/letter/s/d9b06d/32.png) [@SimonDavis](https://forum.certara.com/u/SimonDavis)\ **Post date:** [April 24, 2026, 2:05pm UTC](https://forum.certara.com/t/nlme-error-population-pk-model/4383/2 "2026-04-24T14:05:47Z")
this could be caused by an issue with the data file, or by your installation. I recommend that you email your project to [support@certara.com](mailto:support@certara.com) Simon. ---
**Author:** ![Harikrishna\_Devalapa](https://avatars.discourse-cdn.com/v4/letter/h/ecc23a/32.png) [@Harikrishna\_Devalapa](https://forum.certara.com/u/Harikrishna_Devalapa)\ **Post date:** [April 24, 2026, 3:50pm UTC](https://forum.certara.com/t/nlme-error-population-pk-model/4383/3 "2026-04-24T15:50:32Z")
Thank you for your reply. I did re-install the software and still getting the same error. ---
**Author:** ![Harikrishna\_Devalapa](https://avatars.discourse-cdn.com/v4/letter/h/ecc23a/32.png) [@Harikrishna\_Devalapa](https://forum.certara.com/u/Harikrishna_Devalapa)\ **Post date:** [April 24, 2026, 3:54pm UTC](https://forum.certara.com/t/nlme-error-population-pk-model/4383/4 "2026-04-24T15:54:37Z")
Hi Simon, My email doesn’t allow to send out attachments. Is there a way to upload my workflow here? Thanks ---
**Author:** ![SimonDavis](https://avatars.discourse-cdn.com/v4/letter/s/d9b06d/32.png) [@SimonDavis](https://forum.certara.com/u/SimonDavis)\ **Post date:** [April 24, 2026, 8:34pm UTC](https://forum.certara.com/t/nlme-error-population-pk-model/4383/5 "2026-04-24T20:34:54Z")
you can create a support ticket directly in the portal; [Certara Product Support - Jira Service Management](https://certara.atlassian.net/servicedesk/customer/portal/1071) ---
**Author:** ![Harikrishna\_Devalapa](https://avatars.discourse-cdn.com/v4/letter/h/ecc23a/32.png) [@Harikrishna\_Devalapa](https://forum.certara.com/u/Harikrishna_Devalapa)\ **Post date:** [April 25, 2026, 1:41am UTC](https://forum.certara.com/t/nlme-error-population-pk-model/4383/6 "2026-04-25T01:41:10Z")
Thank you. Uploaded phx nlme workflow in the portal. Hope it will be fixed soon. ---
**Author:** ![Samer\_Mouksassi](https://avatars.discourse-cdn.com/v4/letter/s/ce7236/32.png) [@Samer\_Mouksassi](https://forum.certara.com/u/Samer_Mouksassi)\ **Post date:** [April 30, 2026, 8:50am UTC](https://forum.certara.com/t/nlme-error-population-pk-model/4383/7 "2026-04-30T08:50:06Z")
can you share the pml code are your trying to freeze an epsilon ? can you reproduce the error on a different dataset ? ---
**Author:** ![Harikrishna\_Devalapa](https://avatars.discourse-cdn.com/v4/letter/h/ecc23a/32.png) [@Harikrishna\_Devalapa](https://forum.certara.com/u/Harikrishna_Devalapa)\ **Post date:** [April 30, 2026, 1:52pm UTC](https://forum.certara.com/t/nlme-error-population-pk-model/4383/8 "2026-04-30T13:52:34Z")
Initially i tried with data from 5 subjects and same error found in executing the model. Below is the model text. Thanks test(){ cfMicro(A1, Cl / V, Cl2 / V, Cl2 / V2, first = (Aa = Ka)) dosepoint(Aa) C = A1 / V error(CEps = 1) observe(CObs = C + CEps \* sqrt(1 + C^2 \* (CMultStdev/sigma())^2)) stparm(Ka = tvKa \* exp(nKa)) stparm(V = tvV \* exp(nV)) stparm(V2 = tvV2 \* exp(nV2)) stparm(Cl = tvCl \* exp(nCl)) stparm(Cl2 = tvCl2 \* exp(nCl2)) stparm(CMultStdev = tvCMultStdev) fixef(tvKa = c(0, 0.5725, )) fixef(tvV = c(0, 0.016, )) fixef(tvV2 = c(0, 0.01, )) fixef(tvCl = c(0, -0.1, )) fixef(tvCl2 = c(0, 0.001, )) fixef(tvCMultStdev = c(0, 0.59269079444988, )) ranef(diag(nV, nCl, nKa, nV2, nCl2) = c(1, 1, 1, 1, 1)) } ---
**Author:** ![Samer\_Mouksassi](https://avatars.discourse-cdn.com/v4/letter/s/ce7236/32.png) [@Samer\_Mouksassi](https://forum.certara.com/u/Samer_Mouksassi)\ **Post date:** [May 1, 2026, 8:18pm UTC](https://forum.certara.com/t/nlme-error-population-pk-model/4383/9 "2026-05-01T20:18:49Z")
why is the initial estimate for tvCl negative ? ---
**Author:** ![Bhim\_Bahadur](https://avatars.discourse-cdn.com/v4/letter/b/f17d59/32.png) [@Bhim\_Bahadur](https://forum.certara.com/u/Bhim_Bahadur)\ **Post date:** [May 2, 2026, 5:57pm UTC](https://forum.certara.com/t/nlme-error-population-pk-model/4383/10 "2026-05-02T17:57:08Z")
Error could be your Temp File issue ---
**Author:** ![Harikrishna\_Devalapa](https://avatars.discourse-cdn.com/v4/letter/h/ecc23a/32.png) [@Harikrishna\_Devalapa](https://forum.certara.com/u/Harikrishna_Devalapa)\ **Post date:** [May 15, 2026, 3:23pm UTC](https://forum.certara.com/t/nlme-error-population-pk-model/4383/11 "2026-05-15T15:23:42Z")
Yes, the issue is with phx temp file and after fixing it model run successfully. However, upon attempting to re-run it after couple of days, I encountered the following error message. The system cannot find the file specified. what might be causing this issue? Thanks