diff --git a/client/app.cpp b/client/app.cpp
index 7b8e10c3b2..b8dfefd79a 100644
--- a/client/app.cpp
+++ b/client/app.cpp
@@ -571,6 +571,12 @@ int ACTIVE_TASK::get_free_slot(RESULT* rp) {
             if (is_dir(path)) {
                 retval = client_clean_out_dir(path, "get_free_slot()");
                 if (!retval) break;
+                if (log_flags.slot_debug) {
+                    msg_printf(rp->project, MSG_INFO,
+                        "[slot] failed to clean out dir: %s",
+                        boincerror(retval)
+                    );
+                }
             }
         } else {
             retval = make_slot_dir(j);
diff --git a/client/sandbox.cpp b/client/sandbox.cpp
index 5a3191739b..3caa6b571a 100644
--- a/client/sandbox.cpp
+++ b/client/sandbox.cpp
@@ -271,6 +271,12 @@ int delete_project_owned_file(const char* path, bool retry) {
         } while (dtime() < start + FILE_RETRY_INTERVAL);
     }
     if (retval) {
+        if (log_flags.slot_debug) {
+            msg_printf(0, MSG_INFO,
+                "[slot] failed to remove file %s: %s",
+                path, boincerror(retval)
+            );
+        }
         safe_strcpy(boinc_failed_file, path);
         return ERR_UNLINK;
     }