diff --git a/src/common.cpp b/src/common.cpp
index bd4fa8e3c..825f84bfc 100644
--- a/src/common.cpp
+++ b/src/common.cpp
@@ -2435,10 +2435,10 @@ void redirect_tty_output() {
 /// Display a failed assertion message, dump a stack trace if possible, then die.
 [[noreturn]] void __fish_assert(const char *msg, const char *file, size_t line, int error) {
     if (error) {
-        FLOG(error, L"%s:%zu: failed assertion: %s: errno %d (%s)", file, line, msg, error,
+        FLOGF(error, L"%s:%zu: failed assertion: %s: errno %d (%s)", file, line, msg, error,
              std::strerror(error));
     } else {
-        FLOG(error, L"%s:%zu: failed assertion: %s", file, line, msg);
+        FLOGF(error, L"%s:%zu: failed assertion: %s", file, line, msg);
     }
     show_stackframe(L'E', 99, 1);
     abort();
diff --git a/src/complete.cpp b/src/complete.cpp
index 750d9dbc6..78b2e88bf 100644
--- a/src/complete.cpp
+++ b/src/complete.cpp
@@ -906,7 +906,7 @@ bool completer_t::complete_param(const wcstring &cmd_orig, const wcstring &popt,
         }
     };
 
-    // FLOG(error, L"\nThinking about looking up completions for %ls\n", cmd.c_str());
+    // FLOGF(error, L"\nThinking about looking up completions for %ls\n", cmd.c_str());
     bool head_exists = builtin_exists(cmd);
     // Only reload environment variables if builtin_exists returned false, as an optimization
     if (head_exists == false) {
diff --git a/src/env.cpp b/src/env.cpp
index 12ab94fb8..5ab4fdb4b 100644
--- a/src/env.cpp
+++ b/src/env.cpp
@@ -140,7 +140,7 @@ void fix_colon_delimited_var(const wcstring &var_name, env_stack_t &vars) {
         std::replace(newstrs.begin(), newstrs.end(), empty, wcstring(L"."));
         int retval = vars.set(var_name, ENV_DEFAULT | ENV_USER, std::move(newstrs));
         if (retval != ENV_OK) {
-            FLOG(error, L"fix_colon_delimited_var failed unexpectedly with retval %d", retval);
+            FLOGF(error, L"fix_colon_delimited_var failed unexpectedly with retval %d", retval);
         }
     }
 }
@@ -1353,7 +1353,7 @@ wcstring env_get_runtime_path() {
 
         if (!uname || check_runtime_path(tmpdir.c_str()) != 0) {
             FLOG(error, L"Runtime path not available.");
-            FLOG(error, L"Try deleting the directory %s and restarting fish.", tmpdir.c_str());
+            FLOGF(error, L"Try deleting the directory %s and restarting fish.", tmpdir.c_str());
             return result;
         }
 
diff --git a/src/env_universal_common.cpp b/src/env_universal_common.cpp
index 81b6185d8..1790a990b 100644
--- a/src/env_universal_common.cpp
+++ b/src/env_universal_common.cpp
@@ -196,11 +196,11 @@ static bool append_file_entry(env_var_t::env_var_flags_t flags, const wcstring &
 
     // Append variable name like "fish_color_cwd".
     if (!valid_var_name(key_in)) {
-        FLOG(error, L"Illegal variable name: '%ls'", key_in.c_str());
+        FLOGF(error, L"Illegal variable name: '%ls'", key_in.c_str());
         success = false;
     }
     if (success && !append_utf8(key_in, result, storage)) {
-        FLOG(error, L"Could not convert %ls to narrow character string", key_in.c_str());
+        FLOGF(error, L"Could not convert %ls to narrow character string", key_in.c_str());
         success = false;
     }
 
@@ -211,7 +211,7 @@ static bool append_file_entry(env_var_t::env_var_flags_t flags, const wcstring &
 
     // Append value.
     if (success && !append_utf8(full_escape(val_in), result, storage)) {
-        FLOG(error, L"Could not convert %ls to narrow character string", val_in.c_str());
+        FLOGF(error, L"Could not convert %ls to narrow character string", val_in.c_str());
         success = false;
     }
 
@@ -448,7 +448,7 @@ bool env_universal_t::write_to_fd(int fd, const wcstring &path) {
     std::string contents = serialize_with_vars(vars);
     if (write_loop(fd, contents.data(), contents.size()) < 0) {
         const char *error = std::strerror(errno);
-        FLOG(error, _(L"Unable to write to universal variables file '%ls': %s"), path.c_str(),
+        FLOGF(error, _(L"Unable to write to universal variables file '%ls': %s"), path.c_str(),
              error);
         success = false;
     }
@@ -464,7 +464,7 @@ bool env_universal_t::move_new_vars_file_into_place(const wcstring &src, const w
     int ret = wrename(src, dst);
     if (ret != 0) {
         const char *error = std::strerror(errno);
-        FLOG(error, _(L"Unable to rename file from '%ls' to '%ls': %s"), src.c_str(), dst.c_str(),
+        FLOGF(error, _(L"Unable to rename file from '%ls' to '%ls': %s"), src.c_str(), dst.c_str(),
              error);
     }
     return ret == 0;
@@ -527,7 +527,7 @@ bool env_universal_t::open_temporary_file(const wcstring &directory, wcstring *o
 
     if (!success) {
         const char *error = std::strerror(saved_errno);
-        FLOG(error, _(L"Unable to open temporary file '%ls': %s"), out_path->c_str(), error);
+        FLOGF(error, _(L"Unable to open temporary file '%ls': %s"), out_path->c_str(), error);
     }
     return success;
 }
@@ -589,7 +589,7 @@ bool env_universal_t::open_and_acquire_lock(const wcstring &path, int *out_fd) {
             }
 #endif
             const char *error = std::strerror(errno);
-            FLOG(error, _(L"Unable to open universal variable file '%ls': %s"), path.c_str(),
+            FLOGF(error, _(L"Unable to open universal variable file '%ls': %s"), path.c_str(),
                  error);
             break;
         }
@@ -1061,7 +1061,7 @@ class universal_notifier_shmem_poller_t : public universal_notifier_t {
         int fd = shm_open(path, O_RDWR | O_CREAT, 0600);
         if (fd < 0) {
             const char *error = std::strerror(errno);
-            FLOG(error, _(L"Unable to open shared memory with path '%s': %s"), path, error);
+            FLOGF(error, _(L"Unable to open shared memory with path '%s': %s"), path, error);
             errored = true;
         }
 
@@ -1071,7 +1071,7 @@ class universal_notifier_shmem_poller_t : public universal_notifier_t {
             struct stat buf = {};
             if (fstat(fd, &buf) < 0) {
                 const char *error = std::strerror(errno);
-                FLOG(error, _(L"Unable to fstat shared memory object with path '%s': %s"), path,
+                FLOGF(error, _(L"Unable to fstat shared memory object with path '%s': %s"), path,
                      error);
                 errored = true;
             }
@@ -1082,7 +1082,7 @@ class universal_notifier_shmem_poller_t : public universal_notifier_t {
         bool set_size = !errored && size < (off_t)sizeof(universal_notifier_shmem_t);
         if (set_size && ftruncate(fd, sizeof(universal_notifier_shmem_t)) < 0) {
             const char *error = std::strerror(errno);
-            FLOG(error, _(L"Unable to truncate shared memory object with path '%s': %s"), path,
+            FLOGF(error, _(L"Unable to truncate shared memory object with path '%s': %s"), path,
                  error);
             errored = true;
         }
@@ -1093,7 +1093,7 @@ class universal_notifier_shmem_poller_t : public universal_notifier_t {
                               MAP_SHARED, fd, 0);
             if (addr == MAP_FAILED) {
                 const char *error = std::strerror(errno);
-                FLOG(error, _(L"Unable to memory map shared memory object with path '%s': %s"),
+                FLOGF(error, _(L"Unable to memory map shared memory object with path '%s': %s"),
                      path, error);
                 this->region = NULL;
             } else {
diff --git a/src/exec.cpp b/src/exec.cpp
index a43b24829..614850745 100644
--- a/src/exec.cpp
+++ b/src/exec.cpp
@@ -792,7 +792,7 @@ static bool exec_block_or_func_process(parser_t &parser, std::shared_ptr<job_t>
         const wcstring func_name = p->argv0();
         auto props = function_get_properties(func_name);
         if (!props) {
-            FLOG(error, _(L"Unknown function '%ls'"), p->argv0());
+            FLOGF(error, _(L"Unknown function '%ls'"), p->argv0());
             return false;
         }
 
diff --git a/src/expand.cpp b/src/expand.cpp
index 7b4e63076..cf206abbd 100644
--- a/src/expand.cpp
+++ b/src/expand.cpp
@@ -224,7 +224,7 @@ static size_t parse_slice(const wchar_t *in, wchar_t **end_ptr, std::vector<long
             }
             // debug( 0, L"Push range idx %d %d", i1, i2 );
             for (long jjj = i1; jjj * direction <= i2 * direction; jjj += direction) {
-                // FLOG(error, L"Expand range [subst]: %i\n", jjj);
+                // FLOGF(error, L"Expand range [subst]: %i\n", jjj);
                 idx.push_back(jjj);
             }
             continue;
diff --git a/src/history.cpp b/src/history.cpp
index b385790ba..a4b6cd84b 100644
--- a/src/history.cpp
+++ b/src/history.cpp
@@ -1238,7 +1238,7 @@ bool history_t::rewrite_to_temporary_file(int existing_fd, int dst_fd) const {
             const history_item_t old_item = decode_item(*local_file, offset);
 
             if (old_item.empty() || deleted_items.count(old_item.str()) > 0) {
-                // FLOG(error, L"Item is deleted : %s\n", old_item.str().c_str());
+                // FLOGF(error, L"Item is deleted : %s\n", old_item.str().c_str());
                 continue;
             }
             // Add this old item.
diff --git a/src/iothread.cpp b/src/iothread.cpp
index 43854dcc8..960e04a20 100644
--- a/src/iothread.cpp
+++ b/src/iothread.cpp
@@ -202,7 +202,7 @@ void iothread_service_completion() {
     } else if (wakeup_byte == IO_SERVICE_RESULT_QUEUE) {
         iothread_service_result_queue();
     } else {
-        FLOG(error, "Unknown wakeup byte %02x in %s", wakeup_byte, __FUNCTION__);
+        FLOGF(error, "Unknown wakeup byte %02x in %s", wakeup_byte, __FUNCTION__);
     }
 }
 
diff --git a/src/parse_execution.cpp b/src/parse_execution.cpp
index e4e4921b7..c35ae9006 100644
--- a/src/parse_execution.cpp
+++ b/src/parse_execution.cpp
@@ -360,7 +360,7 @@ parse_execution_result_t parse_execution_context_t::run_block_statement(
     } else if (auto header = bheader.try_get_child<g::begin_header, 0>()) {
         ret = run_begin_statement(contents);
     } else {
-        FLOG(error, L"Unexpected block header: %ls\n", bheader.node()->describe().c_str());
+        FLOGF(error, L"Unexpected block header: %ls\n", bheader.node()->describe().c_str());
         PARSER_DIE();
     }
     return ret;
@@ -1078,7 +1078,7 @@ parse_execution_result_t parse_execution_context_t::populate_job_process(
             break;
         }
         default: {
-            FLOG(error, L"'%ls' not handled by new parser yet.",
+            FLOGF(error, L"'%ls' not handled by new parser yet.",
                  specific_statement.describe().c_str());
             PARSER_DIE();
             break;
@@ -1382,7 +1382,7 @@ parse_execution_result_t parse_execution_context_t::eval_node(tnode_t<g::stateme
     } else if (auto switchstat = statement.try_get_child<g::switch_statement, 0>()) {
         status = this->run_switch_statement(switchstat);
     } else {
-        FLOG(error, "Unexpected node %ls found in %s", statement.node()->describe().c_str(),
+        FLOGF(error, "Unexpected node %ls found in %s", statement.node()->describe().c_str(),
              __FUNCTION__);
         abort();
     }
diff --git a/src/parse_productions.cpp b/src/parse_productions.cpp
index 5dc43aea1..91f3a9001 100644
--- a/src/parse_productions.cpp
+++ b/src/parse_productions.cpp
@@ -403,7 +403,7 @@ const production_element_t *parse_productions::production_for_token(parse_token_
         case parse_token_type_oror:
         case parse_token_type_end:
         case parse_token_type_terminate: {
-            FLOG(error, "Terminal token type %ls passed to %s", token_type_description(node_type),
+            FLOGF(error, "Terminal token type %ls passed to %s", token_type_description(node_type),
                  __FUNCTION__);
             PARSER_DIE();
             break;
@@ -411,13 +411,13 @@ const production_element_t *parse_productions::production_for_token(parse_token_
         case parse_special_type_parse_error:
         case parse_special_type_tokenizer_error:
         case parse_special_type_comment: {
-            FLOG(error, "Special type %ls passed to %s\n", token_type_description(node_type),
+            FLOGF(error, "Special type %ls passed to %s\n", token_type_description(node_type),
                  __FUNCTION__);
             PARSER_DIE();
             break;
         }
         case token_type_invalid: {
-            FLOG(error, "token_type_invalid passed to %s", __FUNCTION__);
+            FLOGF(error, "token_type_invalid passed to %s", __FUNCTION__);
             PARSER_DIE();
             break;
         }
diff --git a/src/parse_tree.cpp b/src/parse_tree.cpp
index 08aedba62..e05a9b9c2 100644
--- a/src/parse_tree.cpp
+++ b/src/parse_tree.cpp
@@ -257,7 +257,7 @@ static inline parse_token_type_t parse_token_type_from_tokenizer_token(
         case TOK_COMMENT:
             return parse_special_type_comment;
     }
-    FLOG(error, "Bad token type %d passed to %s", (int)tokenizer_token_type, __FUNCTION__);
+    FLOGF(error, "Bad token type %d passed to %s", (int)tokenizer_token_type, __FUNCTION__);
     DIE("bad token type");
     return token_type_invalid;
 }
diff --git a/src/path.cpp b/src/path.cpp
index 7e1f9ff16..6aa81b8b8 100644
--- a/src/path.cpp
+++ b/src/path.cpp
@@ -270,15 +270,15 @@ static void maybe_issue_path_warning(const wcstring &which_dir, const wcstring &
 
     FLOG(error, custom_error_msg.c_str());
     if (path.empty()) {
-        FLOG(error, _(L"Unable to locate the %ls directory."), which_dir.c_str());
-        FLOG(error, _(L"Please set the %ls or HOME environment variable before starting fish."),
+        FLOGF(error, _(L"Unable to locate the %ls directory."), which_dir.c_str());
+        FLOGF(error, _(L"Please set the %ls or HOME environment variable before starting fish."),
              xdg_var.c_str());
     } else {
         const wchar_t *env_var = using_xdg ? xdg_var.c_str() : L"HOME";
-        FLOG(error, _(L"Unable to locate %ls directory derived from $%ls: '%ls'."),
+        FLOGF(error, _(L"Unable to locate %ls directory derived from $%ls: '%ls'."),
              which_dir.c_str(), env_var, path.c_str());
-        FLOG(error, _(L"The error was '%s'."), std::strerror(saved_errno));
-        FLOG(error, _(L"Please set $%ls to a directory where you have write access."), env_var);
+        FLOGF(error, _(L"The error was '%s'."), std::strerror(saved_errno));
+        FLOGF(error, _(L"Please set $%ls to a directory where you have write access."), env_var);
     }
     ignore_result(write(STDERR_FILENO, "\n", 1));
 }
diff --git a/src/postfork.cpp b/src/postfork.cpp
index c8a4b2add..fd7205950 100644
--- a/src/postfork.cpp
+++ b/src/postfork.cpp
@@ -374,7 +374,7 @@ void safe_report_exec_error(int err, const char *actual_cmd, const char *const *
             const char *err = safe_strerror(errno);
             debug_safe(0, "exec: %s", err);
 
-            // FLOG(error, L"The file '%ls' is marked as an executable but could not be run by the
+            // FLOGF(error, L"The file '%ls' is marked as an executable but could not be run by the
             // operating system.", p->actual_cmd);
             break;
         }
diff --git a/src/proc.cpp b/src/proc.cpp
index b41c3247f..80ca11705 100644
--- a/src/proc.cpp
+++ b/src/proc.cpp
@@ -923,7 +923,7 @@ void proc_sanity_check(const parser_t &parser) {
         // More than one foreground job?
         if (j->is_foreground() && !(j->is_stopped() || j->is_completed())) {
             if (fg_job) {
-                FLOG(error, _(L"More than one job in foreground: job 1: '%ls' job 2: '%ls'"),
+                FLOGF(error, _(L"More than one job in foreground: job 1: '%ls' job 2: '%ls'"),
                      fg_job->command_wcstr(), j->command_wcstr());
                 sanity_lose();
             }
@@ -937,13 +937,13 @@ void proc_sanity_check(const parser_t &parser) {
             validate_pointer(p->argv0(), _(L"Process name"), null_ok);
 
             if ((p->stopped & (~0x00000001)) != 0) {
-                FLOG(error, _(L"Job '%ls', process '%ls' has inconsistent state \'stopped\'=%d"),
+                FLOGF(error, _(L"Job '%ls', process '%ls' has inconsistent state \'stopped\'=%d"),
                      j->command_wcstr(), p->argv0(), p->stopped);
                 sanity_lose();
             }
 
             if ((p->completed & (~0x00000001)) != 0) {
-                FLOG(error, _(L"Job '%ls', process '%ls' has inconsistent state \'completed\'=%d"),
+                FLOGF(error, _(L"Job '%ls', process '%ls' has inconsistent state \'completed\'=%d"),
                      j->command_wcstr(), p->argv0(), p->completed);
                 sanity_lose();
             }
diff --git a/src/sanity.cpp b/src/sanity.cpp
index 4bc6b540c..f00dd143e 100644
--- a/src/sanity.cpp
+++ b/src/sanity.cpp
@@ -24,12 +24,12 @@ void sanity_lose() {
 void validate_pointer(const void *ptr, const wchar_t *err, int null_ok) {
     // Test if the pointer data crosses a segment boundary.
     if ((0x00000003l & (intptr_t)ptr) != 0) {
-        FLOG(error, _(L"The pointer '%ls' is invalid"), err);
+        FLOGF(error, _(L"The pointer '%ls' is invalid"), err);
         sanity_lose();
     }
 
     if ((!null_ok) && (ptr == 0)) {
-        FLOG(error, _(L"The pointer '%ls' is null"), err);
+        FLOGF(error, _(L"The pointer '%ls' is null"), err);
         sanity_lose();
     }
 }
diff --git a/src/tokenizer.cpp b/src/tokenizer.cpp
index 0308d8f53..b33f0ba3d 100644
--- a/src/tokenizer.cpp
+++ b/src/tokenizer.cpp
@@ -243,7 +243,7 @@ tok_t tokenizer_t::read_string() {
         } else {
             msg.push_back(L'\n');
         }
-        FLOG(error, msg.c_str(), c, c, int(mode_begin), int(mode));
+        FLOGF(error, msg.c_str(), c, c, int(mode_begin), int(mode));
 #endif
 
         this->buff++;
diff --git a/src/wutil.cpp b/src/wutil.cpp
index 4e8d2762f..90a731e65 100644
--- a/src/wutil.cpp
+++ b/src/wutil.cpp
@@ -131,7 +131,7 @@ const wcstring wgetcwd() {
         return str2wcstring(res);
     }
 
-    FLOG(error, _(L"getcwd() failed with errno %d/%s"), errno, std::strerror(errno));
+    FLOGF(error, _(L"getcwd() failed with errno %d/%s"), errno, std::strerror(errno));
     return wcstring();
 }