diff --git a/src/imports/ods_writer.cpp b/src/imports/ods_writer.cpp
index 91faa3e..66d459d 100644
--- a/src/imports/ods_writer.cpp
+++ b/src/imports/ods_writer.cpp
@@ -73,11 +73,14 @@ std::string build_content_xml(const std::vector<OdsSheet> &sheets) {
     }
 
     std::ostringstream oss;
-    doc.save(oss, "  ", pugi::format_no_declaration | pugi::format_raw);
-    // pugi's `format_no_declaration` drops the `<?xml…?>` line; we want
-    // it. Re-emit explicitly to control encoding.
-    return std::string(R"(<?xml version="1.0" encoding="UTF-8"?>)" "\n")
-           + oss.str();
+    // We added the declaration node explicitly above, so pugi will emit
+    // it. `format_no_declaration` only suppresses *implicit* injection;
+    // setting it here would leave the explicit node in place and silently
+    // duplicate would-be auto-emission elsewhere. Keep format_raw to
+    // avoid pretty-print overhead — the file is read by software, not
+    // humans.
+    doc.save(oss, "", pugi::format_raw);
+    return oss.str();
 }
 
 // Minimum META-INF/manifest.xml that satisfies the spec.
diff --git a/src/tui/commands_export.cpp b/src/tui/commands_export.cpp
index 2fe7f20..7c4a3f7 100644
--- a/src/tui/commands_export.cpp
+++ b/src/tui/commands_export.cpp
@@ -98,12 +98,18 @@ void Tui::RegisterExportCommands() {
                     int total = 0;
                     for (auto &ckv : *sys->connections()) {
                         Connection *c = ckv.second;
-                        // Sheet names: Excel rejects /\?*:[] characters
-                        // (LibreOffice tolerates them but stays portable).
+                        // Sheet names: Excel rejects /\?*:[] characters,
+                        // ODS forbids < > & in raw cell/table names
+                        // (they'd need entity-escaping but a few viewers
+                        // choke on them). Sanitise to underscores.
                         std::string sname = c->name;
                         for (char &ch : sname)
                             if (ch == '/' || ch == '\\' || ch == '?' || ch == '*'
-                                || ch == ':' || ch == '[' || ch == ']') ch = '_';
+                                || ch == ':' || ch == '[' || ch == ']'
+                                || ch == '<' || ch == '>' || ch == '&') ch = '_';
+                        // Sheet names also can't exceed 31 chars in
+                        // Excel; clip aggressively to stay portable.
+                        if (sname.size() > 31) sname = sname.substr(0, 31);
                         OdsSheet *s = w.add_sheet(sname);
                         const char *hdr[] = {
                             "transform",