diff --git a/lib/decode65b.f90 b/lib/decode65b.f90
index 9f5a6658c..821286d0d 100644
--- a/lib/decode65b.f90
+++ b/lib/decode65b.f90
@@ -9,6 +9,7 @@ subroutine decode65b(s2,nflip,nadd,mode65,ntrials,naggressive,ndepth,      &
   character mycall*12,hiscall*12,hisgrid*6
   save
 
+  if(nqd.eq.-99) stop                !Silence compiler warning
   do j=1,63
      k=mdat(j)                       !Points to data symbol
      if(nflip.lt.0) k=mdat2(j)
diff --git a/lib/decoder.f90 b/lib/decoder.f90
index 8f1d4e4ef..f693a4ce7 100644
--- a/lib/decoder.f90
+++ b/lib/decoder.f90
@@ -160,6 +160,7 @@ contains
     character*22 decoded
     character*3 cflags
 
+    if(ich.eq.-99) stop                         !Silence compiler warning
     if (have_sync) then
        decoded=decoded0
        cflags='   '
@@ -226,10 +227,11 @@ contains
     integer, intent(in) :: nsum
     integer, intent(in) :: minsync
 
-    integer i,n
-    logical have_sync,is_deep,is_average
+    integer i
+    logical is_deep,is_average
     character decoded*22,csync*2,cflags*3
 
+    if(width.eq.-9999.0) stop              !Silence compiler warning
 !$omp critical(decode_results)
     decoded=decoded0
     cflags='   '
diff --git a/lib/jt4_decode.f90 b/lib/jt4_decode.f90
index 57292d63c..3540b0c1a 100644
--- a/lib/jt4_decode.f90
+++ b/lib/jt4_decode.f90
@@ -130,6 +130,8 @@ contains
        blank='                      '
        ccfblue=0.
        ccfred=0.
+! Silence compiler warnings
+       if(dttol.eq.-99.0 .and. emedelay.eq.-99.0 .and. nagain) stop
     endif
 
     zz=0.
diff --git a/lib/jt65_decode.f90 b/lib/jt65_decode.f90
index 2d70df99f..80b8f9a97 100644
--- a/lib/jt65_decode.f90
+++ b/lib/jt65_decode.f90
@@ -336,6 +336,8 @@ contains
        s3save=0.
        s1save=0.
        nsave=1           !### ???
+! Silence compiler warnings
+       if(nagain .and. ndeepave.eq.-99 .and. neme.eq.-99) stop
     endif
 
     do i=1,64
diff --git a/lib/jt9_decode.f90 b/lib/jt9_decode.f90
index d6e2ece58..d862504af 100644
--- a/lib/jt9_decode.f90
+++ b/lib/jt9_decode.f90
@@ -42,6 +42,7 @@ contains
     common/decstats/ntry65a,ntry65b,n65a,n65b,num9,numfano
     save ccfred,red2
 
+    if(nexp_decode.eq.-99) stop     !Silence compiler warning
     this%callback => callback
     if(nmode.eq.9 .and. nsubmode.ge.1) then
        call decode9w(nfqso,ntol,nsubmode,ss,id2,sync,nsnr,xdt,freq,msg)
diff --git a/lib/timer_module.f90 b/lib/timer_module.f90
index 167e9c9f7..59675c166 100644
--- a/lib/timer_module.f90
+++ b/lib/timer_module.f90
@@ -19,5 +19,6 @@ contains
     implicit none
     character(len=8), intent(in) :: dname
     integer, intent(in) :: k
+    if(dname.eq.'99999999' .and. k.eq.9999) stop  !Silence compiler warnings
   end subroutine null_timer
 end module timer_module