diff --git a/src/XrdChecksum.cc b/src/XrdChecksum.cc
index 6691393..94481cb 100644
--- a/src/XrdChecksum.cc
+++ b/src/XrdChecksum.cc
@@ -195,6 +195,24 @@ int ChecksumManager::Set(const char *lfn, const char *cksname, const char *chksv
     return XrdCksManager::Set(pfn.c_str(), cks);
 }
 
+int ChecksumManager::Del(const char *lfn, unsigned digests)
+{
+    std::string pfn = this->LFN2PFN(lfn);
+    auto del_digest = [&](const char *digest_name) {
+        std::string checksum_name = ATTR_PREFIX;
+        checksum_name += digest_name;
+        XrdSysXAttrActive->Del(checksum_name.c_str(), pfn.c_str());
+    };
+
+    if (digests & ChecksumManager::CKSUM) del_digest("CKSUM");
+    if (digests & ChecksumManager::ADLER32) del_digest("ADLER32");
+    if (digests & ChecksumManager::CRC32) del_digest("CRC32");
+    if (digests & ChecksumManager::MD5) del_digest("MD5");
+    if (digests & ChecksumManager::CVMFS) del_digest("CVMFS");
+
+    return 0;
+}
+
 int        ChecksumManager::Ver(  const char *lfn, XrdCksData &Cks)
 {
     return XrdCksManager::Ver(lfn, Cks);
@@ -243,4 +261,3 @@ std::string ChecksumManager::LFN2PFN(const char* lfn) {
     pfn = pfn_cstr;
     return pfn;
 }
-
diff --git a/src/XrdChecksum.hh b/src/XrdChecksum.hh
index 147be22..308b1f3 100644
--- a/src/XrdChecksum.hh
+++ b/src/XrdChecksum.hh
@@ -109,6 +109,7 @@ public:
 
     int Set(const char *pfn, const ChecksumState &state);
     int Set(const char *pfn, const char *cksname, const char *chksvalue);
+    int Del(const char *pfn, unsigned digests);
 
 
     virtual ~ChecksumManager() {}
@@ -140,4 +141,4 @@ private:
 
 
 
-#endif
\ No newline at end of file
+#endif
diff --git a/src/multiuser.cpp b/src/multiuser.cpp
index 522cff3..39b75f7 100644
--- a/src/multiuser.cpp
+++ b/src/multiuser.cpp
@@ -173,20 +173,33 @@ int     MultiuserFile::Open(const char *path, int Oflag, mode_t Mode, XrdOucEnv
 
 ssize_t MultiuserFile::Write(const void *buffer, off_t offset, size_t size)
 {
+    bool checksum_abandoned = false;
 
     if ((offset != m_nextoff) && m_state) 
     {   
         std::stringstream ss;
-        ss << "Out-of-order writes not supported while running checksum. " << m_fname;
+        ss << "Non-sequential write detected; disabling checksum calculation for " << m_fname;
         m_log.Emsg("Write", ss.str().c_str());
-        return -ENOTSUP;
+        delete m_state;
+        m_state = NULL;
+        checksum_abandoned = true;
     }
 
     auto result = m_wrapped->Write(buffer, offset, size);
-    if (result >= 0) {m_nextoff += result;}
-    if (m_state)
+    if (result >= 0)
+    {
+        m_nextoff = offset + result;
+    }
+    if (checksum_abandoned && result > 0 && g_checksum_manager)
+    {
+        UserSentry sentry(m_client, m_log);
+        if (sentry.IsValid()) {
+            g_checksum_manager->Del(m_fname.c_str(), m_digests);
+        }
+    }
+    if (m_state && result > 0)
     {
-        m_state->Update(static_cast<const unsigned char*>(buffer), size);
+        m_state->Update(static_cast<const unsigned char*>(buffer), static_cast<size_t>(result));
     }
     return result;
 }