If your PROC NLMIXED program contains the NTHREADS= option in the PROC NLMIXED statement and a RANDOM statement, the following messages might occur in the log:

ERROR: An unknown error has occurred during the likelihood computation with NTHREADS= option.

ERROR: Message file "t1c6en" is not found.

There is no workaround for this issue.

Note: This issue occurs in SAS/STAT^® on SAS^® 9.4M3 (TS1M3) and later releases. Hot fixes will be available for SAS^® 9.4M7 (TS1M7), SAS^® 9.4M8 (TS1M8), and SAS^® 9.4M9 (TS1M9). In addition, this issue is fixed in SAS/STAT^® on SAS^® Viya^® 2025.06.